Thanks a lot for your answer! No further questions. (Not for the moment,
that is.)

then the intermediate results are built up in the parameter list and
so you don't need to preserve the function call stack you can just
reuse the same space at each iteration (in otherwords it's essentially
a loop).

It's interesting that you can think of a loop as of a recursive function
call that doesn't have to remember where it came from because it doesn't
have to go back.