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 A199720 #8 Feb 08 2025 22:27:01
%S A199720 1,6,7,5,7,1,3,3,5,8,1,7,7,0,1,5,2,7,0,4,0,5,4,3,4,8,9,1,5,2,9,3,0,4,
%T A199720 6,0,2,9,7,1,7,0,1,7,0,7,7,6,4,1,4,8,9,9,7,3,1,7,4,6,6,7,6,8,1,8,4,0,
%U A199720 9,5,0,6,8,2,0,7,2,6,1,6,0,3,0,4,1,5,2,6,7,8,4,1,6,2,3,6,8,4,4
%N A199720 Decimal expansion of x>0 satisfying x^2-x*cos(x)=3*sin(x).
%C A199720 See A199597 for a guide to related sequences. The Mathematica program includes a graph.
%H A199720 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A199720 1.67571335817701527040543489152930460297170170...
%t A199720 a = 1; b = -1; c = 3;
%t A199720 f[x_] := a*x^2 + b*x*Cos[x]; g[x_] := c*Sin[x]
%t A199720 Plot[{f[x], g[x]}, {x, -Pi, Pi}, {AxesOrigin -> {0, 0}}]
%t A199720 r = x /. FindRoot[f[x] == g[x], {x, 1.6, 1.7}, WorkingPrecision -> 110]
%t A199720 RealDigits[r] (* A199720 *)
%Y A199720 Cf. A199597.
%K A199720 nonn,cons
%O A199720 1,2
%A A199720 _Clark Kimberling_, Nov 09 2011