Pi nieoczywisty iloczyn z naturalnymi

[Eariu52]

\(\displaystyle{ \prod_{n=1}^{ \infty} \frac{\left( 2n\right) ^{3} }{\left( 2n\right) ^{3} -1 } \cdot \frac{\left( 2n+1\right) ^{3} +1 }{\left( 2n+1\right) ^{3}} = \frac{ \pi ^{2} }{8} }\)