iterateM package:List

iterateM :: Monad m => (a -> m a) -> m a -> ListT m a
List Control.Monad.ListT.Funcs
iterateM :: List l => (a -> ItemM l a) -> ItemM l a -> l a
List Data.List.Class
Monadic version of iterate. Can be used to produce trees given a children of node function. 
import Data.List.Tree (bfsLayers)
take 3 $ bfsLayers (iterateM (\i -> [i*2, i*2+1]) [1] :: ListT [] Int)
[[1],[2,3],[4,5,6,7]]