sub get_new_numbers {
    my ($num, $string) = @_;
    my ($mat, $last5) = $string =~ m/^(\w*)(\w{5})$/ or die "doesn't match";
    my @numbers;
    for (1 .. $num) {
        push @numbers, $mat . ++$last5; # automagie
    }
    return @numbers;
}