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 A199873 #8 Feb 08 2025 22:34:49
%S A199873 8,6,6,9,7,4,0,6,9,0,6,4,8,2,4,9,6,9,6,7,4,6,0,5,5,9,7,4,3,0,7,1,9,0,
%T A199873 7,3,0,4,7,1,6,6,5,8,0,6,2,5,3,7,4,4,2,2,3,1,0,4,8,2,5,2,2,0,3,9,0,5,
%U A199873 3,5,0,4,5,0,9,1,6,2,5,1,6,0,4,8,2,8,8,0,5,1,5,2,0,7,5,7,8,4,9
%N A199873 Decimal expansion of x>0 satisfying 4*x^2-4*x*cos(x)=sin(x).
%C A199873 See A199597 for a guide to related sequences. The Mathematica program includes a graph.
%H A199873 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A199873 0.86697406906482496967460559743071907304716...
%t A199873 a = 4; b = -4; c = 1;
%t A199873 f[x_] := a*x^2 + b*x*Cos[x]; g[x_] := c*Sin[x]
%t A199873 Plot[{f[x], g[x]}, {x, -2, 2}, {AxesOrigin -> {0, 0}}]
%t A199873 r = x /. FindRoot[f[x] == g[x], {x, .86, .87}, WorkingPrecision -> 110]
%t A199873 RealDigits[r] (* A199873 *)
%Y A199873 Cf. A199597.
%K A199873 nonn,cons
%O A199873 0,1
%A A199873 _Clark Kimberling_, Nov 11 2011