Question Number 158914 by amin96 last updated on 10/Nov/21
$$\underset{\boldsymbol{\mathrm{n}}=\mathrm{0}} {\overset{\infty} {\sum}}\frac{\mathrm{1}}{\left(\mathrm{3}\boldsymbol{\mathrm{n}}+\mathrm{1}\right)^{\mathrm{3}} }=? \\ $$
n-0-1-3n-1-3-