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);
}