2, 3, 5,7,11,?, 17

The answer is 13.

The sequence is a list of prime numbers. A prime number is a natural number greater than 1 that is not a product of two smaller natural numbers. The first few prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23, and 29.

In this sequence, each number is 2 more than the previous number. Therefore, the next number in the sequence is 13.