You missed the negatives and the 0, however if you needed to count all the negatives that would take you forever.
11
11
11.
that does not make any sense
The answer is 15 because the pattern is subtract one, add two
11, -10, 9
9, 10, 11 and 12
15
The counting sequence is making increments of 11,that is, the n-th term will = 11 x nn = 12,t = 12 x 11= 132
The next figure would be 21, followed by 11 & 10.
4 5 6 7 8 9 10 11 12 13
A "calculation error".