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 A197806 #7 Feb 07 2025 16:44:04
%S A197806 1,0,2,1,6,8,9,9,5,4,0,9,2,1,8,5,2,2,0,3,1,5,5,7,0,2,8,7,9,5,7,5,9,1,
%T A197806 6,0,6,4,7,7,2,2,6,0,3,6,7,2,4,5,8,6,4,8,3,1,5,7,6,0,9,1,9,2,9,7,6,1,
%U A197806 6,7,7,6,8,7,5,6,2,3,1,5,3,7,7,5,2,7,4,3,0,0,8,8,4,9,3,7,7,6,7
%N A197806 Decimal expansion of x>0 having x^2=2*cos(x).
%C A197806 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A197806 x=1.0216899540921852203155702879575916064772260...
%t A197806 a = 1; b = 0; c = 2;
%t A197806 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A197806 Plot[{f[x], g[x]}, {x, -1.5, 1.5}]
%t A197806 r1 = x /. FindRoot[f[x] == g[x], {x, 1, 1.1}, WorkingPrecision -> 110]
%t A197806 RealDigits[r1] (* A197806 *)
%Y A197806 Cf. A197737.
%K A197806 nonn,cons
%O A197806 1,3
%A A197806 _Clark Kimberling_, Oct 20 2011