-- Exercice from slide 42/82

dividers n = [k | k <- [2..(n-1)], rem n k == 0]
dividersf n = filter (\k -> rem n k == 0) [2..(n-1)]

primer n = [i | i <- [2..(n-1)], null (dividers i)]
primerf n = filter (\i -> null (dividersf i)) [2..(n-1)]

square n = n * n

-- Exercice from slide 50
primeinf = [i | i <- [2..], null (dividers i)]