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 A348573 #10 Oct 24 2021 08:44:45
%S A348573 4,8,4,8,2,9,1,0,6,9,9,5,6,8,7,6,4,6,3,1,0,4,0,1,4,1,4,2,2,1,7,3,0,5,
%T A348573 7,4,7,2,4,4,6,9,9,5,2,8,2,3,9,7,3,2,1,4,5,6,2,6,6,5,7,3,6,6,0,3,9,7,
%U A348573 4,5,0,3,2,5,5,8,5,4,6,8,2,0,9,1,0,9,7,0,2,7,1,4,5,6,1,3,1,1,9,3,3,5,4,1,5,8,0,7,6,5
%N A348573 Decimal expansion of exp(-1) * (Ei(1) - gamma).
%F A348573 Equals Sum_{k>=1} (-1)^(k+1) * H(k) / k!, where H(k) is the k-th harmonic number.
%F A348573 Equals -Integral_{x=0..1} exp(-x)*log(1-x) dx. - _Amiram Eldar_, Oct 23 2021
%e A348573 0.48482910699568764631040141422173057472446995282397321...
%t A348573 RealDigits[Exp[-1] (ExpIntegralEi[1] - EulerGamma), 10, 110] [[1]]
%o A348573 (PARI) (-real(eint1(-1))-Euler)/exp(1) \\ _Michel Marcus_, Oct 24 2021
%Y A348573 Cf. A001008, A001113, A001620, A002805, A091725, A229837, A283743, A347952.
%K A348573 nonn,cons
%O A348573 0,1
%A A348573 _Ilya Gutkovskiy_, Oct 23 2021