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

my $sample = "041424344454647484940414";
$sample =~ /([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])([0-9])/; # 24 times the same pattern
print "$1$3$5$7$9$11$13$15$17$19$21$23\n";

__END__
$ perl test.pl
012345678901