use String::Combination qw(combination);
my @comb = combination('12345678',8);
print "@comb[6..12]\n@comb[62..68]\n";

##</code><code>##

23456781 32456781 34256781 34526781 34562781 34567281 34567821
23456781 32456781 34256781 34526781 34562781 34567281 34567821