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]);