use strict;
use warnings;
use Algorithm::Combinatorics qw( variations );
use constant PIN => 4;

my $count = 0;

for my $pre (variations([ 0, 2 .. 9 ], PIN - 1))
{
    print join('', @$pre), "1\t";
    ++$count;
}

print "\nTotal combinations: $count\n";