Difficulty: Easy  Medium
Pre requisites: Basic mathematics
Problem link:
Problem:
To find the nth number in the series:
2 3 7 13 27…
Explanation:
Here the series can be interpreted in two ways.

It is a series where the number at nth position is
T(n)=T(n1)+2*T(n2)

It can also be interpreted as,
T(n)= 2*T(n1)+1 ,if n is odd
T(n)=2*T(n1)1 ,if n is even
The solution has been provided using 1st interpretation.
Problem setter’s solution: SOLUTION