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 A333205 #4 Jun 14 2020 22:50:25
%S A333205 1,2,7,6,4,8,5,0,4,3,5,7,7,2,1,9,0,7,9,5,0,5,7,8,8,1,0,3,2,6,5,2,2,0,
%T A333205 2,0,8,9,7,8,9,8,2,3,6,7,9,9,7,6,8,4,1,1,9,8,1,6,7,9,7,5,4,6,2,5,4,9,
%U A333205 4,7,4,4,2,7,0,8,3,8,0,3,3,9,9,5,1,1
%N A333205 Decimal expansion of arclength between inflection points of y = 1/(1 + x^2).
%e A333205 arclength = 1.2764850435772190795057881032652202089789823679976841...
%t A333205 s = Integrate[Sqrt[1 + 4 x^2/(1 + x^2)^4], {x, -Sqrt[1/3], Sqrt[1/3]}]
%t A333205 r = N[s, 200]
%t A333205 RealDigits[r][[1]]
%Y A333205 Cf. A333202, A333203.
%K A333205 nonn,cons,easy
%O A333205 1,2
%A A333205 _Clark Kimberling_, Jun 12 2020