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 A201290 #10 Jan 30 2025 16:02:23
%S A201290 5,5,4,4,5,6,9,9,7,7,4,7,8,3,1,8,1,8,2,8,9,5,9,8,7,4,8,3,7,7,3,3,9,8,
%T A201290 6,1,9,5,6,5,7,4,5,4,4,2,1,4,6,9,5,0,6,9,4,8,6,8,8,2,8,4,0,5,5,5,6,2,
%U A201290 1,0,4,3,2,5,3,6,7,7,2,8,8,5,2,2,3,6,7,1,9,7,3,9,4,8,8,6,9,2,2
%N A201290 Decimal expansion of x satisfying 2*x^2 + 1 = cot(x) and 0 < x < Pi.
%C A201290 See A201280 for a guide to related sequences. The Mathematica program includes a graph.
%H A201290 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A201290 0.5544569977478318182895987483773398619...
%t A201290 a = 2; c = 1;
%t A201290 f[x_] := a*x^2 + c; g[x_] := Cot[x]
%t A201290 Plot[{f[x], g[x]}, {x, 0, Pi/2}, {AxesOrigin -> {0, 0}}]
%t A201290 r = x /. FindRoot[f[x] == g[x], {x, .55, .56}, WorkingPrecision -> 110]
%t A201290 RealDigits[r] (* A201290 *)
%Y A201290 Cf. A201280.
%K A201290 nonn,cons
%O A201290 0,1
%A A201290 _Clark Kimberling_, Nov 29 2011