Question

3 4 6 9 13 18 24 What is the next number

Answer 1

3-4 = 1
6-9 = 3
13-18 = 5
24-31 = 7


I think the next number is 31

Answer 2

3 4 6 9 13 18 24 31 39 48 58
 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10