Bug: Attempting to calculate a double sum crashes the CAS
12-07-2015, 10:06 PM (This post was last modified: 12-08-2015 07:33 AM by quinyu.)
Post: #1
 quinyu Junior Member Posts: 44 Joined: Dec 2015
Bug: Attempting to calculate a double sum crashes the CAS
Calculating the following double sum causes a calculator crash:

While I understand that the closed form is nasty (involves the Psi function, plus the Euler-Mascheroni constant), the Prime could just say "no idea" instead of crashing. (Solution from Wolfram Alpha. TI nSpire CAS just returns the expression.)

This is Software Version 2015 6 17 (8151), HW ver C, CAS version 1.1.2-11, OS 0.037.526
12-07-2015, 10:42 PM
Post: #2
 quinyu Junior Member Posts: 44 Joined: Dec 2015
RE: Bug: Attempting to calculate a double sum crashes the CAS
HP 50g delivers a half-solution, giving

12-07-2015, 10:54 PM
Post: #3
 DrD Senior Member Posts: 1,133 Joined: Feb 2014
RE: Bug: Attempting to calculate a double sum crashes the CAS
Does this work on Wolfram, Matlab, et al?
12-07-2015, 11:42 PM (This post was last modified: 12-08-2015 07:34 AM by quinyu.)
Post: #4
 quinyu Junior Member Posts: 44 Joined: Dec 2015
RE: Bug: Attempting to calculate a double sum crashes the CAS
Wolfram Alpha gives identical result. (Sorry, earlier I thought that Mathematica would too - no, see below.) Maple 18 gives:
(some little editing to keep style consistent, and factor things a little)

MuPAD gives the same half-solution as the HP 50g. Matlab R2015a also.
12-08-2015, 07:41 AM
Post: #5
 quinyu Junior Member Posts: 44 Joined: Dec 2015
RE: Bug: Attempting to calculate a double sum crashes the CAS
Best sum that I could find with Mathematica 10.0 is:
, where H_n is the nth harmonic number. This is the one I like the most, so far.
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