What is the difference between sixth and fifth terms of the sequence 2,4,7, __

What is the difference between sixth and fifth terms of the sequence 2,4,7, ___ whose n^th term is n + 2^n-1

A 3

B 6

C 16

D 17

Correct Answer: Option D

here,

an=n+2n−1

so, sixth term, a6=6+26−1=38

fifth terms of the sequence,a5=5+25−1=21;

The difference is 38-21=17.