Slow generation of "look and say" sequence

LookAndSaySlow.hs

import Data.List
import System.IO

say :: Integer -> Integer
say = read . concatMap saygroup . group . show
    where saygroup s = (show $ length s) ++ [head s]
look_and_say :: [Integer]
look_and_say = 1 : map say look_and_say

pr (x,y) = do
  hPrint stderr x
  print x
  print (x,y)

main :: IO ()
main = mapM_ pr (zip [0..] look_and_say)