Coding challenge CoderBreakfast Avions

-- http://thecodersbreakfast.net/index.php?post/2013/02/18/Coding-challenge-maman-les-petits-avions

import Data.Char (ord)

syracuse :: [Int] -> [Int]
syracuse n = case n of
                1 : _ -> reverse n
                x : _ -> if mod x 2 == 0 then syracuse((div x 2) : n) else syracuse((x*3+1) : n)

continous :: (Int -> Bool) -> [Int] -> [Int] -> [Int]
continous f n r = case n of
            [] -> r
            x : y -> if f x then continous f (dropWhile f n) (length (takeWhile f n) : r) else continous f y r

getData :: Int -> [Int]
getData n = let syr = syracuse [n] in
            [length syr, maximum (continous (>=n) syr []), maximum syr]

challenge :: String -> [Int]
challenge n = getData (sum (map (ord) n))