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 A278326 #18 Sep 08 2022 08:46:18
%S A278326 1,2,0,1,3,9,8,7,8,0,2,7,6,5,7,7,8,2,4,1,9,4,5,1,5,0,5,5,7,5,6,1,3,5,
%T A278326 1,1,6,8,0,8,0,2,5,2,5,0,1,5,6,0,5,3,6,0,6,6,1,9,4,0,0,5,5,1,5,6,5,7,
%U A278326 9,2,6,2,6,5,3,6,3,6,2,1,3,8,5,1,2,2,0,8,1,5,4,1,0,3,3,7,4,5,0,9,7,6,3,2,8
%N A278326 Decimal expansion of gamma/log(2)^2.
%H A278326 Alois P. Heinz, <a href="/A278326/b278326.txt">Table of n, a(n) for n = 1..10000</a>
%F A278326 Equals -Integral_{x = -infinity..infinity} x*2^x*exp(-2^x) dx.
%F A278326 Equals A001620/A253191 = A100668/A002162.
%e A278326 1.2013987802765778241945150557561351168...
%t A278326 RealDigits[EulerGamma/Log[2]^2,10,120][[1]] (* _Harvey P. Dale_, Dec 07 2017 *)
%o A278326 (PARI) Euler/log(2)^2 \\ _Michel Marcus_, Nov 19 2016
%o A278326 (Magma) SetDefaultRealField(RealField(100)); R:= RealField(); EulerGamma(R)/Log(2)^2; // _G. C. Greubel_, Sep 05 2018
%Y A278326 Cf. A001620, A002162, A100668, A253191.
%K A278326 nonn,cons
%O A278326 1,2
%A A278326 _Alois P. Heinz_, Nov 18 2016