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 A319830 #19 Jan 20 2019 02:51:54
%S A319830 1,3,2,0,7,3,0,4,0,0,8,6,9,6,3,6,6,6,5,4,8,8,6,1,4,8,2,7,7,8,0,7,2,6,
%T A319830 2,0,7,5,2,3,2,4,4,7,9,5,1,8,2,5,9,6,0,7,0,6,6,7,8,7,8,5,8,5,8,6,6,3,
%U A319830 0,3,4,9,7,2,9,7,7,2,4,3,7,4,8,1,2,5,0,3,8,5,9,2,1,9,6,6,7,2,1,7,3,9,1,7,4
%N A319830 Decimal expansion of Integral_{0..oo} (x^(1/x-x)) dx.
%F A319830 Equals Integral_{0..oo} (x^(1/x-x)) dx (definition).
%F A319830 Equals Integral_{0..1} (x^(1/x-x) * (1 + 1/x^2) ) dx.
%F A319830 Equals Integral_{0..oo} ( (x + sqrt(x^2 + 4))/2 )^(-x) dx.
%e A319830 1.3207304008696366654886148277807262075232447951825960706678785858663...
%p A319830 evalf(Int(x^(1/x-x), x = 0..infinity), 120);
%t A319830 RealDigits[NIntegrate[x^(1/x - x), {x, 0, Infinity}, WorkingPrecision -> 120]][[1]] (* _Vaclav Kotesovec_, Jan 15 2019 *)
%Y A319830 Cf. A229191.
%K A319830 nonn,cons
%O A319830 1,2
%A A319830 _Sam Coutteau_, Sep 28 2018
%E A319830 More terms from _Vaclav Kotesovec_, Jan 15 2019