formula

\[x^{2n+1}+y^{2n+1}=(x+y)(x^{2n}-x^{2n-1}y+\cdots-xy^{2n-1}+y^{2n})\]

'Beauty is truth, truth beauty,'-that is all Ye know on earth, and all ye need to know.
John Keats,"Ode on a Grecian Urn"





















● - ◯ - ● - ◯ - ●