Ian Macphail wrote: > put 100 into n > put n * (n + 1) * (2 * n - 2) / 6 into total > > ;) > > _________________ Oops! forgot it was the square of the sum. put 100 into n put n * (n + 1) / 2 into a put n * (n + 1) * (2 * n + 1) / 6 into b put a * a - b into total