Also cross posted with no explanation why the suggested solution didn't work.
library(RcppAlgos)
twin200 <- primeSieve(200)
i <- which(diff(twin200) == 2)
cbind(twin1 = twin200[i], twin2 = twin200[i + 1L])
#> twin1 twin2
#> [1,] 3 5
#> [2,] 5 7
#> [3,] 11 13
#> [4,] 17 19
#> [5,] 29 31
#> [6,] 41 43
#> [7,] 59 61
#> [8,] 71 73
#> [9,] 101 103
#> [10,] 107 109
#> [11,] 137 139
#> [12,] 149 151
#> [13,] 179 181
#> [14,] 191 193
#> [15,] 197 199