use Modern::Perl;
use Algorithm::Combinatorics qw /variations_with_repetition/;
use List::Util qw /sum/;

my @triangulars;
push @triangulars, $_ * ( $_ + 1 ) / 2 for 0 .. 12;

my $iterator = variations_with_repetition( \@triangulars, 3 );

my @results;
$results[ sum @$_ ] = join ' + ', @$_ while $_ = $iterator->next;

say "$_ = $results[$_]" for 0 .. 80;