Thread: [SOLVED] Sum of squares of integers

Hi

Can anyone give me some ideas as to why the following equation is useful in mathematics please?

1^2 + 2^2 + 3^2 + ... + n^2 = (1/6)*n*(n+1)*(2n+1)

I can only think of integration from first principles for x^2 (rectangles under graph)

Any help much appreciated!

Well, it's a sum of a series, and it is a great example to show how the proof of induction works.