outer(1:6, 1:6, "+") + c(1:6)
## [,1] [,2] [,3] [,4] [,5] [,6]
## [1,] 3 4 5 6 7 8
## [2,] 5 6 7 8 9 10
## [3,] 7 8 9 10 11 12
## [4,] 9 10 11 12 13 14
## [5,] 11 12 13 14 15 16
## [6,] 13 14 15 16 17 18