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 A377143 #14 Oct 19 2024 18:07:11
%S A377143 3,3,0,4,9,4,6,0,6,2,9,2,6,4,7,2,1,8,0,1,6,2,6,6,7,8,3,2,5,2,7,8,1,4,
%T A377143 3,4,7,3,6,3,8,3,9,9,6,3,2,8,1,2,8,3,9,8,3,5,6,3,1,9,7,8,4,0,7,9,9,6,
%U A377143 9,0,8,5,0,8,4,3,8,3,1,5,1,9,7,0,9,8,2,6,5,2
%N A377143 Decimal expansion of Integral_{x=0..oo} erfc(x)^2 dx, where erfc is the complementary error function.
%H A377143 Paolo Xausa, <a href="/A377143/b377143.txt">Table of n, a(n) for n = 0..10000</a>
%H A377143 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Erfc.html">Erfc</a>.
%F A377143 Equals (2 - sqrt(2))/sqrt(Pi) = A101465/A002161 (cf. eq. 11 in Weisstein link).
%e A377143 0.3304946062926472180162667832527814347363839963...
%t A377143 First[RealDigits[(2 - Sqrt[2])/Sqrt[Pi], 10, 100]]
%Y A377143 Cf. A002161, A101465, A377144.
%K A377143 nonn,cons
%O A377143 0,1
%A A377143 _Paolo Xausa_, Oct 17 2024