00:01
Okay, so it is known that the sum of the squares on, well, the natural numbers, is given by this formula here.
00:08
But the sum, right, where k goes from 1 to n of k squared, that's equal to n times m plus 1, times 2m plus 1, all divided by 6.
00:17
So here we just take n -minus 1 in place of n, and we have 1 over n times the sum, where k goes from 1, 2n minus 1 of k squared.
00:34
Okay, well that's going to be equal to, well, n minus 1 times n minus 1 plus 1 times 2 n minus 2 plus 1, times 2 n minus 2 plus 1, all divided by 6n...