skipper :: Integral a => [(a,b)] -> [b]
skipper xs = map snd $ filter p xs
  where
    p = (==0) . flip mod n . fst
    n = fst $ head xs
skipper :: Integral a => [(a,b)] -> [b]
skipper xs = map snd $ filter p xs
  where
    p = (==0) . flip mod n . fst
    n = fst $ head xs
skipper xs = map snd $ filter p xs
  where
    p = (==0) . flip mod n . fst
    n = fst $ head xs