# Fibonacci: How to think recursively

Mel mwilson at the-wire.com
Sun Aug 29 01:54:54 CEST 2010

```Baba wrote:

> Level: beginner
>
> I would like to know how to approach the following Fibonacci problem:
> How may rabbits do i have after n months?
>
> I'm not looking for the code as i could Google that very easily. I'm
> looking for a hint to put me on the right track to solve this myself
> without looking it up.
>
> my brainstorming so far brought me to a stand still as i can't seem to
> imagine a recursive way to code this:
>
> my attempted rough code:
>
> def fibonacci(n):
>     # base case:
>         result = fibonacci (n-1) + fibonacci (n-2)
>>> this will end up in a mess as it will create overlapping recursions

I don't think this is the base case.  The base case would be one or more
values of `n` that you already know the fibonacci number for.  Your
recursive function can just test for those and return the right answer right
away.  The the expression you've coded contains a good way to handle the
non-base cases.  There's no such problem as "overlapping recursions".

Mel.

```