1 Tạo dãy số đẹp trên R

library(tidyverse)
## ── Attaching packages ─────────────────────────────────────────────────────────────── tidyverse 1.2.1 ──
## ✔ ggplot2 3.2.0     ✔ purrr   0.3.2
## ✔ tibble  2.1.3     ✔ dplyr   0.8.1
## ✔ tidyr   0.8.3     ✔ stringr 1.4.0
## ✔ readr   1.3.1     ✔ forcats 0.4.0
## ── Conflicts ────────────────────────────────────────────────────────────────── tidyverse_conflicts() ──
## ✖ dplyr::filter() masks stats::filter()
## ✖ dplyr::lag()    masks stats::lag()

1.1 Dãy số tiến

1.1.1 Tiến 7 số

Do dãy số bao gồm cả số 0, vì vậy, nhân thêm với 1e7 để được số 0 ở hàng chục , hàng trăm… Sau đó dùng hàm substr để cắt ký tự

sub_bay <- function(num){num %>% format(digit = 10) %>% str_sub(start = 2L, end = 8L)}
sub_sau <- function(num){num %>% format(digit = 10) %>% str_sub(start = 2L, end = 7L)}
sub_nam <- function(num){num %>% format(digit = 10) %>% str_sub(start = 2L, end = 6L)}
sub_bon <- function(num){num %>% format(digit = 10) %>% str_sub(start = 2L, end = 5L)}
sub_ba <- function(num){num %>% format(digit = 10) %>% str_sub(start = 2L, end = 4L)}
v71 <- 1e7 + 0123456 + 1111111 * 0:3
sub_bay(v71)
## [1] "0123456" "1234567" "2345678" "3456789"

1.1.2 Tiến 6 số

v61 <- 1e6 + 012345 + 111111 * 0:4
sub_bay(v61)
## [1] "012345" "123456" "234567" "345678" "456789"

1.2 Dãy số gánh 7 chữ số (aaabaaa)

v72 <- list(a = 1e7 + 1110111 * 0:9,
            b = 1000 * 0:9) %>%
  cross() %>%
  map_dbl(lift(sum))

v72 %>% sub_bay()
##   [1] "0000000" "1110111" "2220222" "3330333" "4440444" "5550555" "6660666"
##   [8] "7770777" "8880888" "9990999" "0001000" "1111111" "2221222" "3331333"
##  [15] "4441444" "5551555" "6661666" "7771777" "8881888" "9991999" "0002000"
##  [22] "1112111" "2222222" "3332333" "4442444" "5552555" "6662666" "7772777"
##  [29] "8882888" "9992999" "0003000" "1113111" "2223222" "3333333" "4443444"
##  [36] "5553555" "6663666" "7773777" "8883888" "9993999" "0004000" "1114111"
##  [43] "2224222" "3334333" "4444444" "5554555" "6664666" "7774777" "8884888"
##  [50] "9994999" "0005000" "1115111" "2225222" "3335333" "4445444" "5555555"
##  [57] "6665666" "7775777" "8885888" "9995999" "0006000" "1116111" "2226222"
##  [64] "3336333" "4446444" "5556555" "6666666" "7776777" "8886888" "9996999"
##  [71] "0007000" "1117111" "2227222" "3337333" "4447444" "5557555" "6667666"
##  [78] "7777777" "8887888" "9997999" "0008000" "1118111" "2228222" "3338333"
##  [85] "4448444" "5558555" "6668666" "7778777" "8888888" "9998999" "0009000"
##  [92] "1119111" "2229222" "3339333" "4449444" "5559555" "6669666" "7779777"
##  [99] "8889888" "9999999"

1.3 Dãy số kép 6 chữ số(aabbcc)

v62 <- list(a = 1e6 + 110000 * 0:9,
            b = 1100 * 0:9,
            c = 11 * 0:9) %>% 
  cross() %>%
  map_dbl(lift(sum))
sub_sau(v62)
##    [1] "000000" "110000" "220000" "330000" "440000" "550000" "660000"
##    [8] "770000" "880000" "990000" "001100" "111100" "221100" "331100"
##   [15] "441100" "551100" "661100" "771100" "881100" "991100" "002200"
##   [22] "112200" "222200" "332200" "442200" "552200" "662200" "772200"
##   [29] "882200" "992200" "003300" "113300" "223300" "333300" "443300"
##   [36] "553300" "663300" "773300" "883300" "993300" "004400" "114400"
##   [43] "224400" "334400" "444400" "554400" "664400" "774400" "884400"
##   [50] "994400" "005500" "115500" "225500" "335500" "445500" "555500"
##   [57] "665500" "775500" "885500" "995500" "006600" "116600" "226600"
##   [64] "336600" "446600" "556600" "666600" "776600" "886600" "996600"
##   [71] "007700" "117700" "227700" "337700" "447700" "557700" "667700"
##   [78] "777700" "887700" "997700" "008800" "118800" "228800" "338800"
##   [85] "448800" "558800" "668800" "778800" "888800" "998800" "009900"
##   [92] "119900" "229900" "339900" "449900" "559900" "669900" "779900"
##   [99] "889900" "999900" "000011" "110011" "220011" "330011" "440011"
##  [106] "550011" "660011" "770011" "880011" "990011" "001111" "111111"
##  [113] "221111" "331111" "441111" "551111" "661111" "771111" "881111"
##  [120] "991111" "002211" "112211" "222211" "332211" "442211" "552211"
##  [127] "662211" "772211" "882211" "992211" "003311" "113311" "223311"
##  [134] "333311" "443311" "553311" "663311" "773311" "883311" "993311"
##  [141] "004411" "114411" "224411" "334411" "444411" "554411" "664411"
##  [148] "774411" "884411" "994411" "005511" "115511" "225511" "335511"
##  [155] "445511" "555511" "665511" "775511" "885511" "995511" "006611"
##  [162] "116611" "226611" "336611" "446611" "556611" "666611" "776611"
##  [169] "886611" "996611" "007711" "117711" "227711" "337711" "447711"
##  [176] "557711" "667711" "777711" "887711" "997711" "008811" "118811"
##  [183] "228811" "338811" "448811" "558811" "668811" "778811" "888811"
##  [190] "998811" "009911" "119911" "229911" "339911" "449911" "559911"
##  [197] "669911" "779911" "889911" "999911" "000022" "110022" "220022"
##  [204] "330022" "440022" "550022" "660022" "770022" "880022" "990022"
##  [211] "001122" "111122" "221122" "331122" "441122" "551122" "661122"
##  [218] "771122" "881122" "991122" "002222" "112222" "222222" "332222"
##  [225] "442222" "552222" "662222" "772222" "882222" "992222" "003322"
##  [232] "113322" "223322" "333322" "443322" "553322" "663322" "773322"
##  [239] "883322" "993322" "004422" "114422" "224422" "334422" "444422"
##  [246] "554422" "664422" "774422" "884422" "994422" "005522" "115522"
##  [253] "225522" "335522" "445522" "555522" "665522" "775522" "885522"
##  [260] "995522" "006622" "116622" "226622" "336622" "446622" "556622"
##  [267] "666622" "776622" "886622" "996622" "007722" "117722" "227722"
##  [274] "337722" "447722" "557722" "667722" "777722" "887722" "997722"
##  [281] "008822" "118822" "228822" "338822" "448822" "558822" "668822"
##  [288] "778822" "888822" "998822" "009922" "119922" "229922" "339922"
##  [295] "449922" "559922" "669922" "779922" "889922" "999922" "000033"
##  [302] "110033" "220033" "330033" "440033" "550033" "660033" "770033"
##  [309] "880033" "990033" "001133" "111133" "221133" "331133" "441133"
##  [316] "551133" "661133" "771133" "881133" "991133" "002233" "112233"
##  [323] "222233" "332233" "442233" "552233" "662233" "772233" "882233"
##  [330] "992233" "003333" "113333" "223333" "333333" "443333" "553333"
##  [337] "663333" "773333" "883333" "993333" "004433" "114433" "224433"
##  [344] "334433" "444433" "554433" "664433" "774433" "884433" "994433"
##  [351] "005533" "115533" "225533" "335533" "445533" "555533" "665533"
##  [358] "775533" "885533" "995533" "006633" "116633" "226633" "336633"
##  [365] "446633" "556633" "666633" "776633" "886633" "996633" "007733"
##  [372] "117733" "227733" "337733" "447733" "557733" "667733" "777733"
##  [379] "887733" "997733" "008833" "118833" "228833" "338833" "448833"
##  [386] "558833" "668833" "778833" "888833" "998833" "009933" "119933"
##  [393] "229933" "339933" "449933" "559933" "669933" "779933" "889933"
##  [400] "999933" "000044" "110044" "220044" "330044" "440044" "550044"
##  [407] "660044" "770044" "880044" "990044" "001144" "111144" "221144"
##  [414] "331144" "441144" "551144" "661144" "771144" "881144" "991144"
##  [421] "002244" "112244" "222244" "332244" "442244" "552244" "662244"
##  [428] "772244" "882244" "992244" "003344" "113344" "223344" "333344"
##  [435] "443344" "553344" "663344" "773344" "883344" "993344" "004444"
##  [442] "114444" "224444" "334444" "444444" "554444" "664444" "774444"
##  [449] "884444" "994444" "005544" "115544" "225544" "335544" "445544"
##  [456] "555544" "665544" "775544" "885544" "995544" "006644" "116644"
##  [463] "226644" "336644" "446644" "556644" "666644" "776644" "886644"
##  [470] "996644" "007744" "117744" "227744" "337744" "447744" "557744"
##  [477] "667744" "777744" "887744" "997744" "008844" "118844" "228844"
##  [484] "338844" "448844" "558844" "668844" "778844" "888844" "998844"
##  [491] "009944" "119944" "229944" "339944" "449944" "559944" "669944"
##  [498] "779944" "889944" "999944" "000055" "110055" "220055" "330055"
##  [505] "440055" "550055" "660055" "770055" "880055" "990055" "001155"
##  [512] "111155" "221155" "331155" "441155" "551155" "661155" "771155"
##  [519] "881155" "991155" "002255" "112255" "222255" "332255" "442255"
##  [526] "552255" "662255" "772255" "882255" "992255" "003355" "113355"
##  [533] "223355" "333355" "443355" "553355" "663355" "773355" "883355"
##  [540] "993355" "004455" "114455" "224455" "334455" "444455" "554455"
##  [547] "664455" "774455" "884455" "994455" "005555" "115555" "225555"
##  [554] "335555" "445555" "555555" "665555" "775555" "885555" "995555"
##  [561] "006655" "116655" "226655" "336655" "446655" "556655" "666655"
##  [568] "776655" "886655" "996655" "007755" "117755" "227755" "337755"
##  [575] "447755" "557755" "667755" "777755" "887755" "997755" "008855"
##  [582] "118855" "228855" "338855" "448855" "558855" "668855" "778855"
##  [589] "888855" "998855" "009955" "119955" "229955" "339955" "449955"
##  [596] "559955" "669955" "779955" "889955" "999955" "000066" "110066"
##  [603] "220066" "330066" "440066" "550066" "660066" "770066" "880066"
##  [610] "990066" "001166" "111166" "221166" "331166" "441166" "551166"
##  [617] "661166" "771166" "881166" "991166" "002266" "112266" "222266"
##  [624] "332266" "442266" "552266" "662266" "772266" "882266" "992266"
##  [631] "003366" "113366" "223366" "333366" "443366" "553366" "663366"
##  [638] "773366" "883366" "993366" "004466" "114466" "224466" "334466"
##  [645] "444466" "554466" "664466" "774466" "884466" "994466" "005566"
##  [652] "115566" "225566" "335566" "445566" "555566" "665566" "775566"
##  [659] "885566" "995566" "006666" "116666" "226666" "336666" "446666"
##  [666] "556666" "666666" "776666" "886666" "996666" "007766" "117766"
##  [673] "227766" "337766" "447766" "557766" "667766" "777766" "887766"
##  [680] "997766" "008866" "118866" "228866" "338866" "448866" "558866"
##  [687] "668866" "778866" "888866" "998866" "009966" "119966" "229966"
##  [694] "339966" "449966" "559966" "669966" "779966" "889966" "999966"
##  [701] "000077" "110077" "220077" "330077" "440077" "550077" "660077"
##  [708] "770077" "880077" "990077" "001177" "111177" "221177" "331177"
##  [715] "441177" "551177" "661177" "771177" "881177" "991177" "002277"
##  [722] "112277" "222277" "332277" "442277" "552277" "662277" "772277"
##  [729] "882277" "992277" "003377" "113377" "223377" "333377" "443377"
##  [736] "553377" "663377" "773377" "883377" "993377" "004477" "114477"
##  [743] "224477" "334477" "444477" "554477" "664477" "774477" "884477"
##  [750] "994477" "005577" "115577" "225577" "335577" "445577" "555577"
##  [757] "665577" "775577" "885577" "995577" "006677" "116677" "226677"
##  [764] "336677" "446677" "556677" "666677" "776677" "886677" "996677"
##  [771] "007777" "117777" "227777" "337777" "447777" "557777" "667777"
##  [778] "777777" "887777" "997777" "008877" "118877" "228877" "338877"
##  [785] "448877" "558877" "668877" "778877" "888877" "998877" "009977"
##  [792] "119977" "229977" "339977" "449977" "559977" "669977" "779977"
##  [799] "889977" "999977" "000088" "110088" "220088" "330088" "440088"
##  [806] "550088" "660088" "770088" "880088" "990088" "001188" "111188"
##  [813] "221188" "331188" "441188" "551188" "661188" "771188" "881188"
##  [820] "991188" "002288" "112288" "222288" "332288" "442288" "552288"
##  [827] "662288" "772288" "882288" "992288" "003388" "113388" "223388"
##  [834] "333388" "443388" "553388" "663388" "773388" "883388" "993388"
##  [841] "004488" "114488" "224488" "334488" "444488" "554488" "664488"
##  [848] "774488" "884488" "994488" "005588" "115588" "225588" "335588"
##  [855] "445588" "555588" "665588" "775588" "885588" "995588" "006688"
##  [862] "116688" "226688" "336688" "446688" "556688" "666688" "776688"
##  [869] "886688" "996688" "007788" "117788" "227788" "337788" "447788"
##  [876] "557788" "667788" "777788" "887788" "997788" "008888" "118888"
##  [883] "228888" "338888" "448888" "558888" "668888" "778888" "888888"
##  [890] "998888" "009988" "119988" "229988" "339988" "449988" "559988"
##  [897] "669988" "779988" "889988" "999988" "000099" "110099" "220099"
##  [904] "330099" "440099" "550099" "660099" "770099" "880099" "990099"
##  [911] "001199" "111199" "221199" "331199" "441199" "551199" "661199"
##  [918] "771199" "881199" "991199" "002299" "112299" "222299" "332299"
##  [925] "442299" "552299" "662299" "772299" "882299" "992299" "003399"
##  [932] "113399" "223399" "333399" "443399" "553399" "663399" "773399"
##  [939] "883399" "993399" "004499" "114499" "224499" "334499" "444499"
##  [946] "554499" "664499" "774499" "884499" "994499" "005599" "115599"
##  [953] "225599" "335599" "445599" "555599" "665599" "775599" "885599"
##  [960] "995599" "006699" "116699" "226699" "336699" "446699" "556699"
##  [967] "666699" "776699" "886699" "996699" "007799" "117799" "227799"
##  [974] "337799" "447799" "557799" "667799" "777799" "887799" "997799"
##  [981] "008899" "118899" "228899" "338899" "448899" "558899" "668899"
##  [988] "778899" "888899" "998899" "009999" "119999" "229999" "339999"
##  [995] "449999" "559999" "669999" "779999" "889999" "999999"

Nếu dùng hàm cross sẽ bị gặp lỗi 1 số trường hợp như aaaabb, hoặc aabbbb cũng rơi vào nhóm này. Vấn đề này sẽ được xử lý ở dưới, dùng hàm permutation

library(gtools)
v63 <- data.frame(permutations(10, 3, 0:9))
v63 %>% mutate(x4 = paste0(X1, X1,  X2, X2, X3, X3)) %>% pull(x4)
##   [1] "001122" "001133" "001144" "001155" "001166" "001177" "001188"
##   [8] "001199" "002211" "002233" "002244" "002255" "002266" "002277"
##  [15] "002288" "002299" "003311" "003322" "003344" "003355" "003366"
##  [22] "003377" "003388" "003399" "004411" "004422" "004433" "004455"
##  [29] "004466" "004477" "004488" "004499" "005511" "005522" "005533"
##  [36] "005544" "005566" "005577" "005588" "005599" "006611" "006622"
##  [43] "006633" "006644" "006655" "006677" "006688" "006699" "007711"
##  [50] "007722" "007733" "007744" "007755" "007766" "007788" "007799"
##  [57] "008811" "008822" "008833" "008844" "008855" "008866" "008877"
##  [64] "008899" "009911" "009922" "009933" "009944" "009955" "009966"
##  [71] "009977" "009988" "110022" "110033" "110044" "110055" "110066"
##  [78] "110077" "110088" "110099" "112200" "112233" "112244" "112255"
##  [85] "112266" "112277" "112288" "112299" "113300" "113322" "113344"
##  [92] "113355" "113366" "113377" "113388" "113399" "114400" "114422"
##  [99] "114433" "114455" "114466" "114477" "114488" "114499" "115500"
## [106] "115522" "115533" "115544" "115566" "115577" "115588" "115599"
## [113] "116600" "116622" "116633" "116644" "116655" "116677" "116688"
## [120] "116699" "117700" "117722" "117733" "117744" "117755" "117766"
## [127] "117788" "117799" "118800" "118822" "118833" "118844" "118855"
## [134] "118866" "118877" "118899" "119900" "119922" "119933" "119944"
## [141] "119955" "119966" "119977" "119988" "220011" "220033" "220044"
## [148] "220055" "220066" "220077" "220088" "220099" "221100" "221133"
## [155] "221144" "221155" "221166" "221177" "221188" "221199" "223300"
## [162] "223311" "223344" "223355" "223366" "223377" "223388" "223399"
## [169] "224400" "224411" "224433" "224455" "224466" "224477" "224488"
## [176] "224499" "225500" "225511" "225533" "225544" "225566" "225577"
## [183] "225588" "225599" "226600" "226611" "226633" "226644" "226655"
## [190] "226677" "226688" "226699" "227700" "227711" "227733" "227744"
## [197] "227755" "227766" "227788" "227799" "228800" "228811" "228833"
## [204] "228844" "228855" "228866" "228877" "228899" "229900" "229911"
## [211] "229933" "229944" "229955" "229966" "229977" "229988" "330011"
## [218] "330022" "330044" "330055" "330066" "330077" "330088" "330099"
## [225] "331100" "331122" "331144" "331155" "331166" "331177" "331188"
## [232] "331199" "332200" "332211" "332244" "332255" "332266" "332277"
## [239] "332288" "332299" "334400" "334411" "334422" "334455" "334466"
## [246] "334477" "334488" "334499" "335500" "335511" "335522" "335544"
## [253] "335566" "335577" "335588" "335599" "336600" "336611" "336622"
## [260] "336644" "336655" "336677" "336688" "336699" "337700" "337711"
## [267] "337722" "337744" "337755" "337766" "337788" "337799" "338800"
## [274] "338811" "338822" "338844" "338855" "338866" "338877" "338899"
## [281] "339900" "339911" "339922" "339944" "339955" "339966" "339977"
## [288] "339988" "440011" "440022" "440033" "440055" "440066" "440077"
## [295] "440088" "440099" "441100" "441122" "441133" "441155" "441166"
## [302] "441177" "441188" "441199" "442200" "442211" "442233" "442255"
## [309] "442266" "442277" "442288" "442299" "443300" "443311" "443322"
## [316] "443355" "443366" "443377" "443388" "443399" "445500" "445511"
## [323] "445522" "445533" "445566" "445577" "445588" "445599" "446600"
## [330] "446611" "446622" "446633" "446655" "446677" "446688" "446699"
## [337] "447700" "447711" "447722" "447733" "447755" "447766" "447788"
## [344] "447799" "448800" "448811" "448822" "448833" "448855" "448866"
## [351] "448877" "448899" "449900" "449911" "449922" "449933" "449955"
## [358] "449966" "449977" "449988" "550011" "550022" "550033" "550044"
## [365] "550066" "550077" "550088" "550099" "551100" "551122" "551133"
## [372] "551144" "551166" "551177" "551188" "551199" "552200" "552211"
## [379] "552233" "552244" "552266" "552277" "552288" "552299" "553300"
## [386] "553311" "553322" "553344" "553366" "553377" "553388" "553399"
## [393] "554400" "554411" "554422" "554433" "554466" "554477" "554488"
## [400] "554499" "556600" "556611" "556622" "556633" "556644" "556677"
## [407] "556688" "556699" "557700" "557711" "557722" "557733" "557744"
## [414] "557766" "557788" "557799" "558800" "558811" "558822" "558833"
## [421] "558844" "558866" "558877" "558899" "559900" "559911" "559922"
## [428] "559933" "559944" "559966" "559977" "559988" "660011" "660022"
## [435] "660033" "660044" "660055" "660077" "660088" "660099" "661100"
## [442] "661122" "661133" "661144" "661155" "661177" "661188" "661199"
## [449] "662200" "662211" "662233" "662244" "662255" "662277" "662288"
## [456] "662299" "663300" "663311" "663322" "663344" "663355" "663377"
## [463] "663388" "663399" "664400" "664411" "664422" "664433" "664455"
## [470] "664477" "664488" "664499" "665500" "665511" "665522" "665533"
## [477] "665544" "665577" "665588" "665599" "667700" "667711" "667722"
## [484] "667733" "667744" "667755" "667788" "667799" "668800" "668811"
## [491] "668822" "668833" "668844" "668855" "668877" "668899" "669900"
## [498] "669911" "669922" "669933" "669944" "669955" "669977" "669988"
## [505] "770011" "770022" "770033" "770044" "770055" "770066" "770088"
## [512] "770099" "771100" "771122" "771133" "771144" "771155" "771166"
## [519] "771188" "771199" "772200" "772211" "772233" "772244" "772255"
## [526] "772266" "772288" "772299" "773300" "773311" "773322" "773344"
## [533] "773355" "773366" "773388" "773399" "774400" "774411" "774422"
## [540] "774433" "774455" "774466" "774488" "774499" "775500" "775511"
## [547] "775522" "775533" "775544" "775566" "775588" "775599" "776600"
## [554] "776611" "776622" "776633" "776644" "776655" "776688" "776699"
## [561] "778800" "778811" "778822" "778833" "778844" "778855" "778866"
## [568] "778899" "779900" "779911" "779922" "779933" "779944" "779955"
## [575] "779966" "779988" "880011" "880022" "880033" "880044" "880055"
## [582] "880066" "880077" "880099" "881100" "881122" "881133" "881144"
## [589] "881155" "881166" "881177" "881199" "882200" "882211" "882233"
## [596] "882244" "882255" "882266" "882277" "882299" "883300" "883311"
## [603] "883322" "883344" "883355" "883366" "883377" "883399" "884400"
## [610] "884411" "884422" "884433" "884455" "884466" "884477" "884499"
## [617] "885500" "885511" "885522" "885533" "885544" "885566" "885577"
## [624] "885599" "886600" "886611" "886622" "886633" "886644" "886655"
## [631] "886677" "886699" "887700" "887711" "887722" "887733" "887744"
## [638] "887755" "887766" "887799" "889900" "889911" "889922" "889933"
## [645] "889944" "889955" "889966" "889977" "990011" "990022" "990033"
## [652] "990044" "990055" "990066" "990077" "990088" "991100" "991122"
## [659] "991133" "991144" "991155" "991166" "991177" "991188" "992200"
## [666] "992211" "992233" "992244" "992255" "992266" "992277" "992288"
## [673] "993300" "993311" "993322" "993344" "993355" "993366" "993377"
## [680] "993388" "994400" "994411" "994422" "994433" "994455" "994466"
## [687] "994477" "994488" "995500" "995511" "995522" "995533" "995544"
## [694] "995566" "995577" "995588" "996600" "996611" "996622" "996633"
## [701] "996644" "996655" "996677" "996688" "997700" "997711" "997722"
## [708] "997733" "997744" "997755" "997766" "997788" "998800" "998811"
## [715] "998822" "998833" "998844" "998855" "998866" "998877"

1.4 Dãy số lặp (abcabc)

Phần này hơi phức tạp hơn 1 tí (do phải lặp 3 ký tự, mà 3 ký tự này không được trùng nhau). Như vậy ta phải dùng chỉnh hợp (permutation))

v63 <- data.frame(permutations(10, 3, 0:9))
v63 %>% mutate(x4 = paste0(X1, X2, X3, X1, X2, X3)) %>% pull(x4)
##   [1] "012012" "013013" "014014" "015015" "016016" "017017" "018018"
##   [8] "019019" "021021" "023023" "024024" "025025" "026026" "027027"
##  [15] "028028" "029029" "031031" "032032" "034034" "035035" "036036"
##  [22] "037037" "038038" "039039" "041041" "042042" "043043" "045045"
##  [29] "046046" "047047" "048048" "049049" "051051" "052052" "053053"
##  [36] "054054" "056056" "057057" "058058" "059059" "061061" "062062"
##  [43] "063063" "064064" "065065" "067067" "068068" "069069" "071071"
##  [50] "072072" "073073" "074074" "075075" "076076" "078078" "079079"
##  [57] "081081" "082082" "083083" "084084" "085085" "086086" "087087"
##  [64] "089089" "091091" "092092" "093093" "094094" "095095" "096096"
##  [71] "097097" "098098" "102102" "103103" "104104" "105105" "106106"
##  [78] "107107" "108108" "109109" "120120" "123123" "124124" "125125"
##  [85] "126126" "127127" "128128" "129129" "130130" "132132" "134134"
##  [92] "135135" "136136" "137137" "138138" "139139" "140140" "142142"
##  [99] "143143" "145145" "146146" "147147" "148148" "149149" "150150"
## [106] "152152" "153153" "154154" "156156" "157157" "158158" "159159"
## [113] "160160" "162162" "163163" "164164" "165165" "167167" "168168"
## [120] "169169" "170170" "172172" "173173" "174174" "175175" "176176"
## [127] "178178" "179179" "180180" "182182" "183183" "184184" "185185"
## [134] "186186" "187187" "189189" "190190" "192192" "193193" "194194"
## [141] "195195" "196196" "197197" "198198" "201201" "203203" "204204"
## [148] "205205" "206206" "207207" "208208" "209209" "210210" "213213"
## [155] "214214" "215215" "216216" "217217" "218218" "219219" "230230"
## [162] "231231" "234234" "235235" "236236" "237237" "238238" "239239"
## [169] "240240" "241241" "243243" "245245" "246246" "247247" "248248"
## [176] "249249" "250250" "251251" "253253" "254254" "256256" "257257"
## [183] "258258" "259259" "260260" "261261" "263263" "264264" "265265"
## [190] "267267" "268268" "269269" "270270" "271271" "273273" "274274"
## [197] "275275" "276276" "278278" "279279" "280280" "281281" "283283"
## [204] "284284" "285285" "286286" "287287" "289289" "290290" "291291"
## [211] "293293" "294294" "295295" "296296" "297297" "298298" "301301"
## [218] "302302" "304304" "305305" "306306" "307307" "308308" "309309"
## [225] "310310" "312312" "314314" "315315" "316316" "317317" "318318"
## [232] "319319" "320320" "321321" "324324" "325325" "326326" "327327"
## [239] "328328" "329329" "340340" "341341" "342342" "345345" "346346"
## [246] "347347" "348348" "349349" "350350" "351351" "352352" "354354"
## [253] "356356" "357357" "358358" "359359" "360360" "361361" "362362"
## [260] "364364" "365365" "367367" "368368" "369369" "370370" "371371"
## [267] "372372" "374374" "375375" "376376" "378378" "379379" "380380"
## [274] "381381" "382382" "384384" "385385" "386386" "387387" "389389"
## [281] "390390" "391391" "392392" "394394" "395395" "396396" "397397"
## [288] "398398" "401401" "402402" "403403" "405405" "406406" "407407"
## [295] "408408" "409409" "410410" "412412" "413413" "415415" "416416"
## [302] "417417" "418418" "419419" "420420" "421421" "423423" "425425"
## [309] "426426" "427427" "428428" "429429" "430430" "431431" "432432"
## [316] "435435" "436436" "437437" "438438" "439439" "450450" "451451"
## [323] "452452" "453453" "456456" "457457" "458458" "459459" "460460"
## [330] "461461" "462462" "463463" "465465" "467467" "468468" "469469"
## [337] "470470" "471471" "472472" "473473" "475475" "476476" "478478"
## [344] "479479" "480480" "481481" "482482" "483483" "485485" "486486"
## [351] "487487" "489489" "490490" "491491" "492492" "493493" "495495"
## [358] "496496" "497497" "498498" "501501" "502502" "503503" "504504"
## [365] "506506" "507507" "508508" "509509" "510510" "512512" "513513"
## [372] "514514" "516516" "517517" "518518" "519519" "520520" "521521"
## [379] "523523" "524524" "526526" "527527" "528528" "529529" "530530"
## [386] "531531" "532532" "534534" "536536" "537537" "538538" "539539"
## [393] "540540" "541541" "542542" "543543" "546546" "547547" "548548"
## [400] "549549" "560560" "561561" "562562" "563563" "564564" "567567"
## [407] "568568" "569569" "570570" "571571" "572572" "573573" "574574"
## [414] "576576" "578578" "579579" "580580" "581581" "582582" "583583"
## [421] "584584" "586586" "587587" "589589" "590590" "591591" "592592"
## [428] "593593" "594594" "596596" "597597" "598598" "601601" "602602"
## [435] "603603" "604604" "605605" "607607" "608608" "609609" "610610"
## [442] "612612" "613613" "614614" "615615" "617617" "618618" "619619"
## [449] "620620" "621621" "623623" "624624" "625625" "627627" "628628"
## [456] "629629" "630630" "631631" "632632" "634634" "635635" "637637"
## [463] "638638" "639639" "640640" "641641" "642642" "643643" "645645"
## [470] "647647" "648648" "649649" "650650" "651651" "652652" "653653"
## [477] "654654" "657657" "658658" "659659" "670670" "671671" "672672"
## [484] "673673" "674674" "675675" "678678" "679679" "680680" "681681"
## [491] "682682" "683683" "684684" "685685" "687687" "689689" "690690"
## [498] "691691" "692692" "693693" "694694" "695695" "697697" "698698"
## [505] "701701" "702702" "703703" "704704" "705705" "706706" "708708"
## [512] "709709" "710710" "712712" "713713" "714714" "715715" "716716"
## [519] "718718" "719719" "720720" "721721" "723723" "724724" "725725"
## [526] "726726" "728728" "729729" "730730" "731731" "732732" "734734"
## [533] "735735" "736736" "738738" "739739" "740740" "741741" "742742"
## [540] "743743" "745745" "746746" "748748" "749749" "750750" "751751"
## [547] "752752" "753753" "754754" "756756" "758758" "759759" "760760"
## [554] "761761" "762762" "763763" "764764" "765765" "768768" "769769"
## [561] "780780" "781781" "782782" "783783" "784784" "785785" "786786"
## [568] "789789" "790790" "791791" "792792" "793793" "794794" "795795"
## [575] "796796" "798798" "801801" "802802" "803803" "804804" "805805"
## [582] "806806" "807807" "809809" "810810" "812812" "813813" "814814"
## [589] "815815" "816816" "817817" "819819" "820820" "821821" "823823"
## [596] "824824" "825825" "826826" "827827" "829829" "830830" "831831"
## [603] "832832" "834834" "835835" "836836" "837837" "839839" "840840"
## [610] "841841" "842842" "843843" "845845" "846846" "847847" "849849"
## [617] "850850" "851851" "852852" "853853" "854854" "856856" "857857"
## [624] "859859" "860860" "861861" "862862" "863863" "864864" "865865"
## [631] "867867" "869869" "870870" "871871" "872872" "873873" "874874"
## [638] "875875" "876876" "879879" "890890" "891891" "892892" "893893"
## [645] "894894" "895895" "896896" "897897" "901901" "902902" "903903"
## [652] "904904" "905905" "906906" "907907" "908908" "910910" "912912"
## [659] "913913" "914914" "915915" "916916" "917917" "918918" "920920"
## [666] "921921" "923923" "924924" "925925" "926926" "927927" "928928"
## [673] "930930" "931931" "932932" "934934" "935935" "936936" "937937"
## [680] "938938" "940940" "941941" "942942" "943943" "945945" "946946"
## [687] "947947" "948948" "950950" "951951" "952952" "953953" "954954"
## [694] "956956" "957957" "958958" "960960" "961961" "962962" "963963"
## [701] "964964" "965965" "967967" "968968" "970970" "971971" "972972"
## [708] "973973" "974974" "975975" "976976" "978978" "980980" "981981"
## [715] "982982" "983983" "984984" "985985" "986986" "987987"

1.5 Số lặp tiến

Dùng hàm tổ hợp combn là ra

v64 <-
  combn(0:9, 3) %>% 
  t() %>% 
  as.data.frame() %>% 
  mutate(v4 = paste0(V1, V2, V3, V1, V2, V3)) %>% 
  pull(v4)

v64
##   [1] "012012" "013013" "014014" "015015" "016016" "017017" "018018"
##   [8] "019019" "023023" "024024" "025025" "026026" "027027" "028028"
##  [15] "029029" "034034" "035035" "036036" "037037" "038038" "039039"
##  [22] "045045" "046046" "047047" "048048" "049049" "056056" "057057"
##  [29] "058058" "059059" "067067" "068068" "069069" "078078" "079079"
##  [36] "089089" "123123" "124124" "125125" "126126" "127127" "128128"
##  [43] "129129" "134134" "135135" "136136" "137137" "138138" "139139"
##  [50] "145145" "146146" "147147" "148148" "149149" "156156" "157157"
##  [57] "158158" "159159" "167167" "168168" "169169" "178178" "179179"
##  [64] "189189" "234234" "235235" "236236" "237237" "238238" "239239"
##  [71] "245245" "246246" "247247" "248248" "249249" "256256" "257257"
##  [78] "258258" "259259" "267267" "268268" "269269" "278278" "279279"
##  [85] "289289" "345345" "346346" "347347" "348348" "349349" "356356"
##  [92] "357357" "358358" "359359" "367367" "368368" "369369" "378378"
##  [99] "379379" "389389" "456456" "457457" "458458" "459459" "467467"
## [106] "468468" "469469" "478478" "479479" "489489" "567567" "568568"
## [113] "569569" "578578" "579579" "589589" "678678" "679679" "689689"
## [120] "789789"

1.6 Số lặp lùi

Chỉ cần nghịch đảo thứ tự các số trong hàm combn, hoặc nghịch đảo thứ tự các biến trong hàm paste0

v65 <-
  combn(9:0, 3) %>% 
  t() %>% 
  as.data.frame() %>% 
  mutate(v4 = paste0(V1, V2, V3, V1, V2, V3)) %>% 
  pull(v4)

v65
##   [1] "987987" "986986" "985985" "984984" "983983" "982982" "981981"
##   [8] "980980" "976976" "975975" "974974" "973973" "972972" "971971"
##  [15] "970970" "965965" "964964" "963963" "962962" "961961" "960960"
##  [22] "954954" "953953" "952952" "951951" "950950" "943943" "942942"
##  [29] "941941" "940940" "932932" "931931" "930930" "921921" "920920"
##  [36] "910910" "876876" "875875" "874874" "873873" "872872" "871871"
##  [43] "870870" "865865" "864864" "863863" "862862" "861861" "860860"
##  [50] "854854" "853853" "852852" "851851" "850850" "843843" "842842"
##  [57] "841841" "840840" "832832" "831831" "830830" "821821" "820820"
##  [64] "810810" "765765" "764764" "763763" "762762" "761761" "760760"
##  [71] "754754" "753753" "752752" "751751" "750750" "743743" "742742"
##  [78] "741741" "740740" "732732" "731731" "730730" "721721" "720720"
##  [85] "710710" "654654" "653653" "652652" "651651" "650650" "643643"
##  [92] "642642" "641641" "640640" "632632" "631631" "630630" "621621"
##  [99] "620620" "610610" "543543" "542542" "541541" "540540" "532532"
## [106] "531531" "530530" "521521" "520520" "510510" "432432" "431431"
## [113] "430430" "421421" "420420" "410410" "321321" "320320" "310310"
## [120] "210210"
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