What the sequence of 2 9 5 13 10 19 17?

Answer 1

If you follow the difference in these numbers:

2 + 7 = 9

9 - 4 = 5

5 + 8 = 13

13 - 3 = 10

10 + 9 = 19

19 - 2 = 17

You can see that the numbers being subtracted and the numbers being added each follow a pattern:

Addition: 7, 8, 9

Subtraction: 4, 3, 2

The next number in the sequence then would be 27, as 9 + 1 = 10 and 17 + 10 = 27. The next one would be 26, as -2 + 1 = -1, and 27 + -1 = 26, and so on:

2 9 5 13 10 19 17 26 37 37 49 50 63 65 ...