I typed
n = var('n')
sum(1/((2n-1)^2(2n+1)^2(2*n+3)^2), n, 0, oo)
sage answered
3/256*pi^2 - 1/32
By hand computation (via Fourier series), and by WolframAlpha I got
3/256*pi^2
Why?
Link to WolframAlpha's result.
(This is my first question. If it is inappropriate here, please tell me where I should ask it. I used the tag "bug", but I of course mean "potential bug". Thank you very much in advance!)