Complete the series: 1, 2, 4, 7, 11, 16, ______?

Complete the series: 1, 2, 4, 7, 11, 16, ______?

Explanation

The pattern of the series is:

+1, +2, +3, +4, +5...

So, the next difference should be +6:

16 + 6 = 22

The correct answer is 22.