gistfile1.hs

-- The Haskell Wiki solution to this still seems like witchcraft.
-- foldr1 lcm [1..20]

c_s :: Int -> [ Int ]
c_s x = nub $ map ( x `mod` ) [ 1..20 ]

p5_iter :: Int -> Int
p5_iter x = case length $ nub $ map ( x `mod` ) [ 1..20 ] of
          1 ->
              x
          _ -> p5_iter (x + 1)

problem_five = p5_iter 1