What comes next in the pattern?

13, 24, 17, 29, 21, 34, 25, 39,

29, 44, 33,?,

49. The pattern is every time you add, you add the next positive number number and every time you subtract, you add the next negative number.

Step-by-step explanation:

13 + 11 = 24

24 - 7 = 17

17 + 12 = 29

29 - 8 = 21

21 + 13 = 34

34 - 9 = 25

25 + 14 = 39

39 - 10 = 29

29 + 15 = 44

44 - 11 = 33

33 + 16 = 49

43 is the answer because it goes up 11 down 7