Suppose that a recursive routine were invoked to calculate F(4). How many times would a recursive call of F(1) occur?
Although you haven't said so explicitly, it seems as though you are talking about Fibonacci sequences, since the usual notation for that in Mathematics/Computer Science classes is F(n), and the routines are recursive. The Fibonacci sequence is defined as:
`F(n)=F(n-1)+F(n-2)` , where `F(2)=1` and `F(1)=1` .
which means that
And we can see that the recursive calls continue as
This means that the call of `F(1)=1` is called only once.