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 A380270 #9 Feb 03 2025 23:01:49
%S A380270 5,0,0,1,0,2,3,3,6,2,7,0,1,7,0,6,0,6,4,1,1,9,5,8,3,7,3,3,8,1,9,2,6,8,
%T A380270 1,2,7,8,0,1,7,7,7,2,5,2,0,1,4,6,9,6,1,7,7,8,2,8,6,4,0,4,4,9,3,8,0,9,
%U A380270 6,7,1,4,7,3,0,3,0,9,2,3,8,7,2,9,5,3,0,7,1,1,1,6,5,2,0,6,8,2,9,8,9,1,4,9,1
%N A380270 Decimal expansion of Integral_{x=1..A070769} li(x) dx (negated), where li(x) is the logarithmic integral.
%C A380270 A070769 is Soldner's constant, where li(A070769)=0.
%C A380270 Integral_{x=0..1} li(x) dx = -log(2) then Integral_{x=0..A070769} li(x) dx = A380270 - log(2) = -1.19324951683011591582919049...
%e A380270 -0.500102336270170606411958373..
%t A380270 y = x /. FindRoot[LogIntegral[x] == 0, {x, 1.5}, WorkingPrecision -> 200]; yy = -Integrate[LogIntegral[x], {x, 1, y}]; RealDigits[yy, 10, 105][[1]]
%Y A380270 Cf. A069284, A070769, A084945, A091723, A244067, A257817, A257818, A257819, A257820, A257821, A270857.
%K A380270 cons,nonn
%O A380270 0,1
%A A380270 _Artur Jasinski_, Jan 18 2025