my @zeck = zeck($ARGV[0]);
print 'zeck(',  $ARGV[0], ') = ', join(' + ', @zeck), "\n";

sub zeck
{
    return $_[0] if is_fibonnacci($_[0]);

    my $count = 0;
    my $prev  = 0;
    my $curr  = 0;

    while (($curr = fibonnacci($count)) < $_[0])
    {
        $prev = $curr;
        $count++;
    }

    return ($prev, zeck($_[0] - $prev));
}