What is the next number - 1, -2, 4, -6, 7, -10, 10, -14, ??

Question

The sequence below contains terms that doesn't have any perfect square factors (except 1).
2, 3, 5, 6, 7, 10, 11, 13, 14, 15...

What is the sum of the square-roots of the terms starting from 2 to the largest two-digit term?

Answer 1

1 -3= -2
-2+6= 4
4 - 10= -6
-6 + 13 = 7
7 - 17 = -10
-10 + 20 = 10
10 - 24 = -14
Now if we look at the sequence
3 6 10 13 17 20 24 , the next is 27
Therefore -14 + 27 = 13
The answer is 13

Answer 2

13 is the answer.

Comments

What is the logic?