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 A114720 #18 Feb 16 2025 08:33:00 %S A114720 4,9,7,1,2,0,7,7,8,1,8,8,3,1,4,1,0,9,9,1,2,7,7,3,7,3,9,6,8,5,3,9,7,7, %T A114720 1,9,8,0,7,2,9,3,6,0,9,5,5,7,7,0,5,1,8,5,9,3,3,2,3,4,2,3,3,9,9,8,4,9, %U A114720 5,5,2,9,0,4,5,5,4,3,4,8,5,2,3,9,1,6,9,9,6,4,9,7,8,3,8,8,1,4,3,4,9,0 %N A114720 Decimal expansion of -(Gamma(1/4)*zeta(1/2))/(8*Pi^(1/4)). %C A114720 Let Xi(s) = -(s + 1/2)*zeta(1/2 - s)*(1/4 - s/2)! / Pi^(1/4 - s/2) be Riemann's (uppercase) Xi function, then the given constant equals Xi(0). - _Peter Luschny_, Jun 28 2021 %H A114720 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Xi-Function.html">Xi-Function</a> %F A114720 Equals -(1/4)!*zeta(1/2)/(2*Pi^(1/4)). - _Peter Luschny_, Jun 27 2021 %e A114720 0.49712077818831410991277373968539771980729360955770518593323423... %t A114720 RealDigits[RiemannXi[1/2], 10, 102][[1]] (* _Jean-François Alcover_, Nov 04 2017 *) %o A114720 (PARI) -(gamma(1/4)*zeta(1/2))/(8*Pi^(1/4)) \\ _Michel Marcus_, Nov 04 2017 %K A114720 nonn,cons %O A114720 0,1 %A A114720 _Eric W. Weisstein_, Dec 27 2005