Find the number that can replace question mark (?) in the series given below: 3, 8, 15, 24, 35, 48, ?

The missing number is 63.

Each term is one less than a perfect square.

2^2-1 = 3, 3^2-1 = 8, 4^2-1 = 15, 5^2-1 = 24.

The differences 5, 7, 9, 11, 13 increase by 2.

48 + 15 = 63, which is 8^2 - 1.