#!/usr/bin/env perl 
use strict;
use warnings;

my @lines = <DATA>;
print shift @lines;
chomp @lines;
my $perline = 8;
my @num;
my @numline = (1 .. $perline);
my $fmt = '%s ' . '%5i' x $perline . "\n";
for my $line (@lines) {
    if ($line =~ /^1/) {
        print join ('   ', @num) . "\n";
        last;
    }
    printf $fmt, $line, @numline;
    push @num, @numline;
    $_ += $perline for @numline;
}

__DATA__
    a       b    c    d    e    f    g    h
aa
bb
cc
dd
aa
bb
cc
dd
aa
bb
cc
dd
1    2    3    4    5    6    7    8    9    10    11    12    13    14    15    16