25. Insert the missing number.: 7, 26, 63, 124, 215, 342, (….)

✅ The correct answer is option B.
Numbers are (23 – 1), (33 – 1), (43 – 1), (53 – 1), (63 – 1), (73 – 1) etc.
So, the next number is (83 – 1) = (512 – 1) = 511.