sub g {
#        1         2         3         4         5
#2345678901234567890123456789012345678901234567890123456
$^=pop;for(1..$^){printf"%$^d",++$,for(0..$@++);print$/}
}

=g(3) OUTPUT
  1
  2  3
  4  5  6

=g(5) OUTPUT
    1
    2    3
    4    5    6
    7    8    9   10
   11   12   13   14   15

=g(7) OUTPUT
      1
      2      3
      4      5      6
      7      8      9     10
     11     12     13     14     15
     16     17     18     19     20     21
     22     23     24     25     26     27     28