heap exhausted

[Martin Stein]

Hi,

though I think there was written enough about this theme, I can't still
understand the following problem (foldl' from the Prelude.hs):

> seq1 x = (3-x):seq1 x
> seq2 x = (3-x):seq2 1
>
> countOne xs = foldl' (\c x -> if x==1 then c+1 else c) 0 xs
>
> num1 n = countOne (take n (seq1 1))
> num2 n = countOne (take n (seq2 1))

num1 needs lots of heap space, num2 needs very few. Why?
(I checked it using ghc and '+RTS -s')

Martin Stein