import Data.IORef

runClosure f = mapM_ f [0..5]

main = do
  x <- newIORef (0, (+ 1))
  runClosure $ \i -> do
    (n,f) <- readIORef x
    print $ f n
    writeIORef x (f n, if i `mod` 2 == 0 then (+ 1) else (* 2))