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 A199867 #10 Feb 08 2025 22:34:39
%S A199867 6,3,5,7,9,4,2,3,3,9,7,1,9,2,6,5,5,1,4,3,5,4,2,6,6,4,2,1,0,0,1,5,9,2,
%T A199867 2,3,2,3,8,8,1,5,0,3,7,1,6,5,9,8,8,6,8,9,6,3,7,8,9,2,5,4,1,7,8,0,3,0,
%U A199867 3,4,3,4,0,1,4,0,4,0,9,4,6,6,6,4,9,4,2,7,1,1,3,1,7,4,3,1,3,0,4,5,5,6,7,6,9,7
%N A199867 Decimal expansion of x > 0 satisfying 4*x^2 - 2*x*cos(x) = sin(x).
%C A199867 See A199597 for a guide to related sequences. The Mathematica program includes a graph.
%H A199867 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A199867 0.63579423397192655143542664210015922323...
%t A199867 a = 4; b = -2; c = 1;
%t A199867 f[x_] := a*x^2 + b*x*Cos[x]; g[x_] := c*Sin[x]
%t A199867 Plot[{f[x], g[x]}, {x, -2, 2}, {AxesOrigin -> {0, 0}}]
%t A199867 r = x /. FindRoot[f[x] == g[x], {x, .63, .64}, WorkingPrecision -> 110]
%t A199867 RealDigits[r] (* A199867 *)
%Y A199867 Cf. A199597.
%K A199867 nonn,cons
%O A199867 0,1
%A A199867 _Clark Kimberling_, Nov 11 2011
%E A199867 a(90) onwards corrected by _Georg Fischer_, Aug 03 2021