Logic question:

Question

1, 1, 2, 3, 5, 8, 13……?
What comes next and why?

Answer 1

21. Apart from the first two numbers each number is the sum of the two preceding numbers. It's the Fibonacci sequence.

Answer 2

Or, the next number it could be the sum of all the preceding numbers +1.
21=8+5+3+2+1+1+1