Larcombe, Peter J., and Larsen, Mogens E. “The Sum 16nΣ2nk=04k( 1/2k)(-1/2k)(-2k 2n-k): A Proof of Its Closed Form”. Utilitas Mathematica 79 (June 9, 2009). Accessed May 8, 2026. https://utilitasmathematica.com/index.php/Index/article/view/628.