How to calculate this sum: $\sum_{1}^{\infty}\frac{1}{n(\sinh(kn))^3}$

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I encountered this summation in Statistical Mechanics. $$\sum_{n=1}^{\infty}\frac{1}{n(\sinh(kn))^3}$$ I know this series converges. Can we find its closed form solution? Here k is some positive real number.