补全以下数列。
1, 2, 4, 7, 11, _
The next number is 16. 

The pattern for this sequence is adding consecutive numbers to the previous number in the sequence. 

1 + 1 = 2 

2 + 2 = 4 

4 + 3 = 7 

7 + 4 = 11 

11 + 5 = 16