What is the maximum number of consecutive positive integers that can be added together to create a sum less than 400?

The infinite series whose terms are the natural numbers 1 + 2 + 3 + 4 + â‹Ż is a divergent series. The nth partial sum of the series is the triangular number {/displaystyle / sum _{k=1}^{n}k={/frac {n (n+1) }{2}},} / sum_{k=1}^n k = / frac{n (n+1) }{2}, which increases without bound as n goes to infinity. Because the sequence of partial sums fails to converge to a finite limit, the series does not have a sum. Although the series seems at first sight not to have any meaningful value at all, it can be manipulated to yield a number of mathematically interesting