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 A346839 #9 Aug 17 2021 09:27:15
%S A346839 2,9,3,4,0,7,9,9,3,0,2,6,0,2,3,3,8,7,4,0,4,7,7,8,4,3,3,9,4,0,2,9,0,0,
%T A346839 2,0,3,8,3,1,4,5,8,8,2,7,1,2,4,8,9,2,6,0,4,5,1,2,1,1,6,7,2,1,5,9,9,5,
%U A346839 4,0,1,4,1,0,9,8,6,9,4,1,6,3,6,6,7,4,1,4,4,8
%N A346839 Decimal expansion of Sum_{n>=0} A346838(n) / n!.
%F A346839 Equals sec(1) - tan(1) = A073448 - A049471. - _Amiram Eldar_, Aug 17 2021
%e A346839 0.29340799302602338740477843394029002038314588271248926...
%p A346839 A := n -> I*(polylog(-n, -I) - exp(I*Pi*n)*polylog(-n, I)) / exp(I*Pi*n/2):
%p A346839 Digits := 120; sum(A(n)/n!, n = 0..infinity): evalf(%)*10^91:
%p A346839 ListTools:-Reverse(convert(floor(%), base, 10));
%t A346839 RealDigits[Sec[1] - Tan[1], 10 , 100][[1]] (* _Amiram Eldar_, Aug 17 2021 *)
%Y A346839 Cf. A049471, A073448, A346838.
%K A346839 nonn,cons
%O A346839 0,1
%A A346839 _Peter Luschny_, Aug 13 2021