if have well-known (jednacinu) equation ((n 1) * n) / 2 = 1 2.. n. Now if the difference between the closest numbers smaller, to get ((n 0,1) * n) / (2 * 0,1) = 0,1 0,2.. n. If the difference between the closest numbers the smallest possible, will obtain ((n 0,0.. 1) * n) / (2 * 0,0.. 1) = 0,0.. 1 0,0.. 2.. n or can transform n ^ 2 / 2 = (0,0.. 1 0,0.. 2.. n) / 0,0.. 1 . For example if n = 10 will obtain ((10 1) * 10) / 2 = 1 2.. 10 or ((10 0,1) * 10) / (2 * 0,1) = 0,1 0,2.. 10 or ((10 0,0.. 1) * 10) / (2 * 0,0.. 1) = 0,0.. 1 0,0.. 2.. 10 can transform (10 ^ 2) / 2 = (0,0.. 1 0,0.. 2.. 10) / 0,0.. 1 Question, which is correct ? Srbin

The computations are a bit different.

If you are summing from 1 to N, and the difference between 2 numbers is , then put (assuming (N-1)/x integer):



and the last term is . Thus you have the sum