Intelligent Mushak Raaj

One day Bappa gave Mushak Raaj an interesting problem to solve and test his knowledge. Bappa also promised to give some gifts and Modaks if Mushak Raaj is able to solve this problem. The problem goes something like this: there is an infinite sequence $S$ of integers, where $S_i$ denotes the $i$th integer in that sequence. The sequence is defined by: - $S_i$ = $2$, for $i = 0$ - $S_i$ = $[A * f(S