Amicable pairs

sub propdivsum (\x) {
    my @l = 1 if x > 1;
    (2 .. x.sqrt.floor).map: -> \d {
        unless x % d { @l.push: d; my \y = x div d; @l.push: y if y != d }
    }
    sum @l
}

(1..20000).race.map: -> $i {
    my $j = propdivsum($i);
    say "$i $j" if $j > $i and $i == propdivsum($j);
}

Output:

220 284
1184 1210
2620 2924
5020 5564
6232 6368
10744 10856
12285 14595
17296 18416