Question Number 220141 by MrGaster last updated on 06/May/25
$$\underset{{n}=\mathrm{1}} {\overset{\infty} {\sum}}\underset{{m}=\mathrm{1}} {\overset{\infty} {\sum}}\frac{\mathrm{1}}{\left({n}^{\mathrm{2}} +{m}^{\mathrm{2}} \right)^{\mathrm{3}/\mathrm{2}} }=? \\ $$
Answered by Nicholas666 last updated on 07/May/25
$$\:\:\:\:\frac{\mathrm{2}\zeta\left(\mathrm{3}\right)}{\pi}\: \\ $$$$ \\ $$