Smart comment because we don't, usually, think in the zero when we use the triangular number [1] (aka, but not, Gauss sum[2]). [1] https://en.wikipedia.org/wik

Smart comment because we don't, usually, think in the zero when we use the triangular number [1] (aka, but not, Gauss sum[2]). [1] https://en.wikipedia.org/wiki/Triangular_number https://en.wikipedia.org/wiki/Triangular_number [2] https://en.wikipedia.org/wiki/Gauss_sum https://en.wikipedia.org/wiki/Gauss_sum