Which of the following numbers will replace the question mark (?) in the given series?
1, 9, 41, 169, ?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 681.
1 + 8 = 9; 9 + (8 × 4) = 41; 41 + (32 × 4) = 169; 169 + (128 × 4) = 681