Re: complex triple sum

*To*: mathgroup at smc.vnet.net*Subject*: [mg125999] Re: complex triple sum*From*: danl at wolfram.com*Date*: Thu, 12 Apr 2012 02:34:42 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <jlp379$16e$1@smc.vnet.net>

On Saturday, April 7, 2012 5:00:09 AM UTC-5, Greg wrote: > I'm having trouble solving this summation and was wondering if anyone could put me on the right track. Here's the problem below. > > Sum from 1 to infinity in steps of 2 for l, m, and n:((-1)^((m - 1)/2))*(m/(n^2 + l^2 + m^2)) > > I've tried using the built in sum functions > > Sum[((-1)^((m - 1)/2))*(m/(n^2 + l^2 + m^2)),{l,1,Infinity,2},{m,1,Infinity,2},{n,1,Infinity,2}] > > but mathematica continuously sums this and never reaches an approximation. Is there any function I'm missing or a way to simplify this? In what sense do you want it summed? Classically, it is divergent. I do not know why Sum takes so long to unravel this though. Daniel Lichtblau Wolfram Research