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 A224518 #30 Dec 15 2024 05:22:07
%S A224518 6,2,1,4,4,9,6,2,4,2,3,5,8,1,3,3,5,7,6,3,9,2,6,5,7,2,8,2,1,5,3,3,9,3,
%T A224518 2,3,8,9,3,1,6,4,6,7,6,9,1,9,7,0,5,4,1,6,9,4,7,9,7,5,5,3,1,6,4,1,9,3,
%U A224518 0,5,6,1,6,2,1,3,7,4,5,2,9,8,7,7,7,5,1,9,2,3,9,0,3,6,6,7,4,5,0,7
%N A224518 Decimal expansion of Integral_{x=0..Infinity} exp(-x)/(1+x^2) dx.
%H A224518 Steven R. Finch, <a href="http://arxiv.org/abs/2001.00578">Errata and addenda to Mathematical Constants</a>, arXiv:2001.00578 [math.HO], 2020-2024, p. 62.
%F A224518 Equals (Pi/2)*cos(1)+cosIntegral(1)*sin(1)-cos(1)*sinIntegral(1).
%F A224518 Equals Integral_{x=0..1} 1/(1+log(x)^2) dx.
%F A224518 Equals Integral_{x=0..Pi/2} exp(-tan(x)) dx. - _Amiram Eldar_, Aug 06 2020
%e A224518 0.621449624235813357639265728215339323893164676919705416947975531641930561621...
%t A224518 (Pi/2)*Cos[1] + CosIntegral[1]*Sin[1] - Cos[1]*SinIntegral[1] // RealDigits[#, 10, 100]& // First
%K A224518 nonn,cons,easy
%O A224518 0,1
%A A224518 _Jean-François Alcover_, Apr 09 2013