primes :: [Int]
primes  =  sieve [2..]

sieve :: [Int] -> [Int]
sieve (p:xs)  =  p : sieve [x | x <- xs, x `mod` p /= 0]

twin_primes :: Int -> [(Int,Int)]
twin_primes k = [(p,q) | (p,q) <- zip primes (tail primes), q == p+2*k]