Solving recurrence relation: Product form Please help in finding the solution of this recursion. 
$$f(n)=\frac{f(n-1) \cdot f(n-2)}{n},$$
where $ f(1)=1$ and $f(2)=2$.

As @Winther commented, letting $a_n=\log f(n)$ one has
$$a_n-a_{n-1}-a_{n-2}=-\log n.$$
We only need a particular solution. Let $F_n$ be the Fibonacci sequence $F_0=F_1=1, F_i=F_{i-1}+F_{i-2}$. And consider 
$$b_n= \sum^n_{i=0}F_i\log (n-i).$$
It is easy to show that 
$$b_n=b_{n-1}+b_{n-2}+\log n.$$
