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 A185197 #32 Sep 28 2022 14:12:43
%S A185197 2,0,2,6,4,2,3,6,7,2,8,4,6,7,5,5,4,2,8,8,7,7,5,8,9,2,6,4,1,9,4,5,5,2,
%T A185197 7,7,8,0,8,7,1,7,5,4,9,3,4,4,4,9,3,0,9,7,6,9,1,2,1,8,0,6,3,7,8,8,3,4,
%U A185197 6,2,4,1,9,2,4,4,7,0,8,8,2,3,8,2,4,1,8,5,4,7,8,5,1,2,4,3,6,7,5
%N A185197 Decimal expansion of 2/Pi^2.
%C A185197 Asymptotic density of the even squarefree numbers (A039956). - _Amiram Eldar_, May 22 2020
%D A185197 C. F. Gauss, Disquisitiones Arithmeticae, Yale, 1965; see p. 360.
%H A185197 Vincenzo Librandi, <a href="/A185197/b185197.txt">Table of n, a(n) for n = 0..3000</a>
%H A185197 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>
%F A185197 Equals 1/(3*zeta(2)). - _Michel Marcus_, Jun 13 2017
%F A185197 Equals -Sum_{k>=1} mu(2*k)/(2*k)^2, where mu is the Möbius function (A008683). - _Amiram Eldar_, Jul 31 2020
%e A185197 .20264236728467554288775892641945527780871754934449309769121...
%t A185197 RealDigits[2/\[Pi]^2,10,100][[1]] (* _Harvey P. Dale_, Mar 16 2011 *)
%o A185197 (PARI) 2/Pi^2 \\ _Charles R Greathouse IV_, Mar 25 2014
%Y A185197 Cf. A008683, A013661, A039956.
%K A185197 cons,nonn
%O A185197 0,1
%A A185197 _N. J. A. Sloane_, Feb 19 2011