gistfile1.hs

import Data.List
import Math.NumberTheory.Primes.Sieve
import Control.Monad
import Debug.Trace



numWays without p =
    let (poor, rich) = splitAt p without
        with = poor ++
               zipWith (+) with rich
    in with

counter = foldl numWays (1 : repeat 0)

main = do
    let ways = counter $ takeWhile (<5000) [fromInteger p | p <- primes]
    print $ ways !! 10
    print $ ways !! 5000