26544

My Solution:

If we pick 3 consecutive numbers, we can label them x-1, x and x+1. This is true for any real number. In the case of 1, 2 and 3; x-1 = 1, x = 2, x+1 = 3. If we find the sum of the algebraic representation of the numbers, we can see that x-1 + x + x+1 is the same as saying 3 multiplied by x (or 3x).

This is why when adding 3 consecutive numbers, the sum is always divisible by 3 (or can be made up of 3 of the same integers).