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 A099286 #16 Jul 14 2025 09:33:50 %S A099286 8,4,2,7,0,0,7,9,2,9,4,9,7,1,4,8,6,9,3,4,1,2,2,0,6,3,5,0,8,2,6,0,9,2, %T A099286 5,9,2,9,6,0,6,6,9,9,7,9,6,6,3,0,2,9,0,8,4,5,9,9,3,7,8,9,7,8,3,4,7,1, %U A099286 7,2,5,4,0,9,6,0,1,0,8,4,1,2,6,1,9,8,3,3,2,5,3,4,8,1,4,4,8,8,8,4,5,4,1,5,8 %N A099286 Decimal expansion of the error function at 1. %H A099286 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Erf.html">Erf</a> %F A099286 Equals 1-A099287. %F A099286 Equals (1/e) Sum_{n >= 0} (1/(n/2)!) - 1. - _Jean-François Alcover_, Jun 14 2020 %F A099286 From _Amiram Eldar_, Jul 22 2020: (Start) %F A099286 Equals (2/sqrt(Pi)) * Integral_{x=0..1} exp(-x^2) dx. %F A099286 Equals (2/sqrt(Pi)) * Sum_{k>=0} (-1)^k/(k! * (2*k + 1)) = (2/sqrt(Pi)) * Sum_{k>=0} (-1)^k/A007680(k). %F A099286 Equals (1/e) * Sum_{k>=1} 1/Gamma(k + 1/2). (End) %e A099286 0.84270079294971486934122063508260925929606699796630290845993789783... %t A099286 RealDigits[ Erf[1], 10, 105][[1]] %o A099286 (PARI) 1 - erfc(1) %Y A099286 Cf. A007680, A099287, A351400. %K A099286 cons,nonn %O A099286 0,1 %A A099286 _Robert G. Wilson v_, Oct 08 2004