Question Number 69538 by mind is power last updated on 24/Sep/19
$${Hello}\:{Verry}\:{Nice}\:{Day}\:{for}\:\:{You} \\ $$$${Find}\:\underset{{k}\geqslant\mathrm{0}} {\sum}\frac{\mathrm{1}}{\left(\mathrm{8}{k}+\mathrm{1}\right)^{\mathrm{2}} } \\ $$
Hello-Verry-Nice-Day-for-You-Find-k-0-1-8k-1-2-