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 A199664 #11 Feb 08 2025 22:26:52
%S A199664 6,6,5,5,9,9,0,7,7,3,3,0,6,7,6,1,5,2,5,0,5,2,6,5,1,9,2,2,6,8,8,5,3,0,
%T A199664 2,8,5,4,3,4,8,9,7,4,7,9,1,5,0,6,1,4,7,2,4,8,9,4,2,4,2,2,3,7,9,0,9,6,
%U A199664 8,0,5,6,1,6,1,3,3,8,6,2,2,1,1,6,4,8,5,2,4,6,3,4,8,5,9,8,9,6,7
%N A199664 Decimal expansion of x > 0 satisfying 3*x^2 + x*cos(x) = 3*sin(x).
%C A199664 See A199597 for a guide to related sequences. The Mathematica program includes a graph.
%H A199664 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A199664 0.6655990773306761525052651922688530...
%t A199664 a = 3; b = 1; c = 3;
%t A199664 f[x_] := a*x^2 + b*x*Cos[x]; g[x_] := c*Sin[x]
%t A199664 Plot[{f[x], g[x]}, {x, -1, 1.5}, {AxesOrigin -> {0, 0}}]
%t A199664 r = x /. FindRoot[f[x] == g[x], {x, .66, .67}, WorkingPrecision -> 110]
%t A199664 RealDigits[r] (* A199664 *)
%Y A199664 Cf. A199597.
%K A199664 nonn,cons
%O A199664 0,1
%A A199664 _Clark Kimberling_, Nov 09 2011
%E A199664 a(88) onwards corrected by _Georg Fischer_, Aug 03 2021