MathDB
Sum of First k Squares

Source:

December 28, 2006

Problem Statement

It is known that, for all positive integers k,k, 12+22+32++k2=k(k+1)(2k+1)6.1^{2}+2^{2}+3^{2}+\cdots+k^{2}=\frac{k(k+1)(2k+1)}{6}. Find the smallest positive integer kk such that 12+22+32++k21^{2}+2^{2}+3^{2}+\cdots+k^{2} is a multiple of 200.200.