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 A199719 #9 Feb 08 2025 22:26:59
%S A199719 1,8,3,7,1,8,8,7,3,0,0,1,5,1,4,3,9,2,4,2,5,7,5,6,9,4,4,1,6,2,2,0,0,8,
%T A199719 2,3,2,5,5,8,4,2,3,7,5,1,1,5,2,9,8,6,0,1,3,5,4,9,2,3,6,1,7,3,4,8,3,1,
%U A199719 2,5,7,1,2,9,0,7,2,5,7,0,9,7,2,6,5,2,8,7,3,8,1,9,8,4,7,6,7,8,4
%N A199719 Decimal expansion of x>0 satisfying x^2-x*cos(x)=4*sin(x).
%C A199719 See A199597 for a guide to related sequences. The Mathematica program includes a graph.
%H A199719 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A199719 1.837188730015143924257569441622008232558...
%t A199719 a = 1; b = -1; c = 4;
%t A199719 f[x_] := a*x^2 + b*x*Cos[x]; g[x_] := c*Sin[x]
%t A199719 Plot[{f[x], g[x]}, {x, -Pi, Pi}, {AxesOrigin -> {0, 0}}]
%t A199719 r = x /. FindRoot[f[x] == g[x], {x, 1.8, 1.9}, WorkingPrecision -> 110]
%t A199719 RealDigits[r] (* A199719 *)
%Y A199719 Cf. A199597.
%K A199719 nonn,cons
%O A199719 1,2
%A A199719 _Clark Kimberling_, Nov 09 2011