This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A353127 #22 Apr 25 2022 09:25:15
%S A353127 1,7,7,4,2,5,3,9,1,9,7,1,2,3,9,4,3,4,5,2,9,1,3,9,0,6,2,8,5,1,0,8,6,1,
%T A353127 2,1,5,7,5,2,9,2,4,7,1,7,4,4,9,9,4,2,4,0,2,4,8,2,6,5,7,3,3,4,5,6,1,6,
%U A353127 1,7,5,8,3,6,3,5,1,0,6,5,9,5,1,4,4,5,8,0,0,2
%N A353127 Decimal expansion of Pi^2/4 - log(2).
%C A353127 Limit of the series u where u(n) = 1/n when n is a square, and u(n) = (-1)^n/n otherwise.
%D A353127 M. Lepez, Les Grands classiques de Mathématiques, Classes préparatoires scientifiques, Analyse, Exercices corrigés et commentés, MP-PC-PT, Bréal, 1995, Exercice 201, p. 29.
%F A353127 Equals A091476 - A002162.
%F A353127 Equals Sum_{k>=1} ( (-1)^k/k + 2/(2*k-1)^2 ).
%e A353127 1.77425391971239434529139062851086121575292471744...
%p A353127 evalf(Pi^2/4 - log(2),100);
%t A353127 RealDigits[Pi^2/4 - Log[2], 10, 100][[1]] (* _Amiram Eldar_, Apr 24 2022 *)
%o A353127 (PARI) Pi^2/4 - log(2) \\ _Michel Marcus_, Apr 24 2022
%Y A353127 Cf. A091476 (Pi^2/4), A002162 (log(2)).
%K A353127 nonn,cons
%O A353127 1,2
%A A353127 _Bernard Schott_, Apr 24 2022