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 A377400 #9 Oct 27 2024 09:23:55
%S A377400 1,0,8,2,6,9,1,1,0,7,6,6,3,4,6,8,1,7,9,7,1,0,4,9,3,1,7,4,2,4,6,2,1,5,
%T A377400 2,8,4,1,9,0,7,1,0,3,8,3,8,7,0,7,2,1,8,4,5,1,1,5,0,6,9,5,8,5,9,4,7,4,
%U A377400 7,1,2,1,2,8,9,8,8,9,9,3,5,8,9,8,8,4,6,3,0,1,7,5,7,0,7,7,8,3,7,8
%N A377400 Decimal expansion of e*(gamma - Ei(-1))/2.
%H A377400 Michael I. Shamos, <a href="http://euro.ecom.cmu.edu/people/faculty/mshamos/cat.pdf">A catalog of the real numbers</a>, (2007). See p. 120.
%F A377400 Equals Sum_{n>=1} (1/n!)*Sum_{k=1..n} 1/(2*k) (see Shamos).
%F A377400 Equals A347952 / 2.
%e A377400 1.08269110766346817971049317424621528419071038...
%t A377400 RealDigits[E(EulerGamma-ExpIntegralEi[-1])/2,10,100][[1]]
%Y A377400 Cf. A000142, A001008, A001113, A001620, A005843, A060746, A099285, A347952, A377401.
%K A377400 nonn,cons
%O A377400 1,3
%A A377400 _Stefano Spezia_, Oct 27 2024