7, 26, 63, 124, 215, 342, (....)	Options:
A) 481	B) 511	C) 421	D) 391	E) 515
The series is (23 - 1), (33 - 1), (43 - 1), (53 - 1), (63 - 1), (73 - 1), ...   Hence, next number is (83 - 1) = 511   Answer is 511
<result>B</result>
7, 26, 63, 124, 215, 342, (....)