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 A222392 #18 Feb 15 2025 02:32:01
%S A222392 5,5,7,3,1,6,9,6,6,4,3,1,0,0,3,9,7,5,3,2,5,7,9,0,4,0,4,9,7,7,5,5,8,2,
%T A222392 4,0,0,5,3,8,3,8,5,3,1,3,5,6,4,6,6,5,3,4,3,0,3,2,4,8,1,2,0,6,4,1,8,2,
%U A222392 9,0,3,0,7,3,2,8,3,4,5,3,5,8,4,2,2,4,5
%N A222392 Decimal expansion of Sum_{n>=1} 1/Gamma(n/2).
%D A222392 Jerome Spanier and Keith B. Oldham, "Atlas of Functions", Hemisphere Publishing Corp., 1987, chapter 43, equation 43:5:12 at page 415.
%H A222392 Vincenzo Librandi, <a href="/A222392/b222392.txt">Table of n, a(n) for n = 1..5000</a>
%F A222392 Equals (1+erf(1))*e+1/sqrt(Pi), where erf is the error function (see A099286).
%e A222392 5.57316966431003975325790404977558240053838531356466534303248120641829030...
%t A222392 RealDigits[(1 + Erf[1]) E + 1/Sqrt[Pi], 10, 90][[1]]
%Y A222392 Cf. A222391.
%Y A222392 Cf. A001113, (Sum_{n>=1} 1/Gamma(n)).
%K A222392 nonn,cons
%O A222392 1,1
%A A222392 _Bruno Berselli_, Mar 19 2013