What number which best completes the sequence below 2 9 5 13 10 19 17?

Answer 1

2 -> 9 = +7

9 -> 5 = -4

5 ->13 = +8

13 -> 10 = -3

10 -> 19 = +9

19 -> 17 = -2

As you can see, every other time, the number is increased. It was originally increased by 7, then 8, then 9. So, the next number should be increased by 10 = 27