Q: In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Problem: 3 , 15 , x , 51 , 53 , 159161 value of x ? 
Options: a ) 17 , b ) 34 , c ) 54 , d ) 64 , e ) 112
A:
a