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 A367563 #8 Nov 23 2023 07:57:25 %S A367563 6,1,4,9,5,2,0,9,4,6,9,6,5,1,0,9,8,0,8,3,9,6,8,1,1,8,5,6,2,3,6,4,1,3, %T A367563 9,3,0,5,1,3,4,5,6,1,7,8,9,5,4,0,3,5,7,2,3,2,6,6,3,8,6,9,3,4,9,9,5,8, %U A367563 8,7,8,9,5,6,1,3,3,4,1,9,5,7,1,1,0,3,5,6,6,3,3,8,5,3,8,9,8,0,3,1,9,9,0 %N A367563 Decimal expansion of Erfi(1/2), where Erfi is the imaginary error function. %H A367563 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Erfi.html">Erfi</a>. %e A367563 0.61495209469651098083968118562364139305134561789540357232663869... %t A367563 N[Erfi[1/2], 110] // RealDigits // First %o A367563 (PARI) -imag(erfc(I/2)) \\ _Michel Marcus_, Nov 23 2023 %K A367563 nonn,cons %O A367563 0,1 %A A367563 _Peter Luschny_, Nov 23 2023