1.  1, 3, 10, 21, 64, 129, 356, 777
A. 10
B. 21
C. 64
D. 129
E. 356

Answer: Option E

Explanation:

A x 2 + 1, B x 3 + 1, C x 2 + 1, D x 3 + 1 and so on.

So, 356 is wrong.