1³+2³+3³+4³+5³+6³+7³+8³+9³+10³+11³+12³+13³+14³+15³+16³+17³+18³+19³+20³+21³+22³+23³+24³+25³+26³+...
Numberphile · 13:41 · Watch on YouTube
The video shows visual, intuitive proofs for the three classic finite power sums — integers, squares, and cubes — culminating in the surprising result that the sum of cubes equals the square of the triangular numbers.