primeFactors :: Int->[Int]
primeFactors n
	| n `mod` divisor == 0 = primeFactors (n `div` divisor):divisor:[]
	| n == 2 = []
	| otherwise = n `mod` divisor `mod` (divisor+1)
            where divisor
	             |primeFactors [] = 2
		     |otherwise = divisor