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 A201328 #10 Jan 30 2025 16:02:20
%S A201328 5,2,2,9,4,1,8,3,0,5,6,4,4,4,6,6,3,1,5,9,1,8,6,1,8,5,6,1,6,3,9,6,6,8,
%T A201328 9,0,9,4,0,6,9,3,6,3,6,5,8,7,5,9,3,0,4,1,0,8,6,5,6,6,1,9,9,0,2,3,3,3,
%U A201328 5,3,0,5,8,9,4,2,9,7,8,5,6,3,9,7,8,7,6,1,9,0,7,2,8,6,4,5,3,4,1
%N A201328 Decimal expansion of x satisfying 10*x^2 - 1 = cot(x) and 0 < x < Pi.
%C A201328 See A201280 for a guide to related sequences. The Mathematica program includes a graph.
%H A201328 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A201328 0.522941830564446631591861856163966890940693...
%t A201328 a = 10; c = -1;
%t A201328 f[x_] := a*x^2 + c; g[x_] := Cot[x]
%t A201328 Plot[{f[x], g[x]}, {x, 0, Pi/2}, {AxesOrigin -> {0, 0}}]
%t A201328 r = x /. FindRoot[f[x] == g[x], {x, .5, .6}, WorkingPrecision -> 110]
%t A201328 RealDigits[r] (* A201328 *)
%Y A201328 Cf. A201280.
%K A201328 nonn,cons
%O A201328 0,1
%A A201328 _Clark Kimberling_, Nov 30 2011