GESSEL, IRA M.; LARCOMBE, PETER J. The sum 16nΣ2nk=04k( 1/2k)(-1/2k)(-2k 2n-k): A third proof of its closed form. Utilitas Mathematica , [S. l.], v. 80, 2009. Disponível em: https://utilitasmathematica.com/index.php/Index/article/view/596. Acesso em: 8 may. 2026.