RosettaCodeData/Task/Prime-decomposition/SequenceL/prime-decomposition-2.sequencel

primeFactorization(num) := primeFactorizationHelp(num, 2, []);

primeFactorizationHelp(num, divisor, factors(1)) :=
        factors when num <= 1
    else
        primeFactorizationHelp(num, divisor + 1, factors) when num mod divisor /= 0
    else
        primeFactorizationHelp(num / divisor, divisor, factors ++ [divisor]);