all possible combinations of the number 1..n

Algorithm::Combinatorics

use Algorithm::Combinatorics qw[ combinations ];;

for my $k ( 1 .. 3 ) { 
    my $i = combinations( [ 1..3 ], $k ); 
    print @$_ while defined( $_ = $i->next );
};;
1
2
3
1 2
1 3
2 3
1 2 3
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