TITLE: Summation using residues
QUESTION [23 upvotes]: In reference to this question about showing that the following interesting series takes on the value
$$\sum_{n=0}^\infty \frac{1}{(2n+1)\operatorname{sinh}((2n+1)\pi)}=\frac{\log(2)}{8}$$
I tried the approach of using the residue theorem, from which one can show that
$$\sum_{n=-\infty}^\infty f(n) = -\sum_k \mathrm{Res}_{z=z_k} [\pi \cot{\pi z} \: f(z)] $$
where $z_k$ are non-integral poles of $\pi \cot{\pi z} f(z)$.  In this case, 
$$f(z) = \frac{\mathrm{csch}{[(2 z+1) \pi]}}{2 z+1}$$
There is a pole of order $1$ at $z=-1/2$.  Note that is is not of order $2$ because $\cot{z} \sim (\pi/2) - z$ as $z \rightarrow \pi/2$.  One may then compute the single residue of $\pi \cot{\pi z} f(z)$ as
$$\mathrm{Res}_{z=z_k} \left [\pi \cot{\pi z} \: \frac{\mathrm{csch}{[(2 z+1) \pi]}}{2 z+1} \right ] = -\frac{\pi}{4} $$
So I get as a value for the posted series as $\pi/8$, which is not correct.  Nevertheless, I cannot locate my error.  Perhaps someone can.  For example, the series obviously converges, and quickly.  But is there an error in my assumption that
$$\lim_{N \rightarrow \infty} \oint_{C_N} dz \: \pi \cot{\pi z} \: \frac{\mathrm{csch}{[(2 z+1) \pi]}}{2 z+1} = 0$$
where $C_N$ is a rectaingle symmetric about the real and imaginary axes, extending from $[-N-1/2,N+1/2]$?  Or is there something else I do not see?

REPLY [4 votes]: Here is one way to consider the series. 
Expand it as 
$\displaystyle \sum_{n=1}^{\infty}\frac{1}{n(e^{\pi n}+1)}-\frac{1}{2}\sum_{n=1}^{\infty}\frac{1}{n(e^{2\pi n}+1)}+\sum_{n=1}^{\infty}\frac{1}{n(e^{\pi n}-1)}-\frac{1}{2}\sum_{n=1}^{\infty}\frac{1}{n(e^{2\pi n}-1)}=\frac{log(2)}{8}$
These are rather famous sums studied by Ramanujan. We can probably find their evaluations in his notebooks or some other place like Plouffe, as was previously mentioned.
Can any of the above sums be evaluated using residues?. 
I think there may be a general formula derived by Ramanujan for sums of this type.
I think I have seen one in terms of Bernoulli numbers. 
Anyway, some thoughts.