.'. Missing number = 33 + 13 = 46.[/
7, 26, 63, 124, 215, 342, ?
Explanation: 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.