#!/usr/bin/env perl
use warnings;
use strict;
use feature qw{ say };

use List::PowerSet qw{ powerset };

my %groups;

while (<DATA>) {
    my @numbers = split;
    for my $ps (@{ powerset(@numbers) }) {
        next if @$ps < 2;
        $groups{"@$ps"}++;
    }
}

for my $group (keys %groups) {
    next if $groups{$group} == 1;
    say "$group repeated $groups{$group} times";
}

__DATA__
1 2 5 9
1 2 5 10
4 5 10 12
5 9 10 11
[download]

Output:

5 9 repeated 2 times
1 2 repeated 2 times
1 5 repeated 2 times
5 10 repeated 3 times
1 2 5 repeated 2 times
2 5 repeated 2 times
[download]

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
[download]