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 A198143 #9 Feb 07 2025 16:44:05
%S A198143 3,6,9,2,3,4,7,7,7,3,9,2,7,9,8,9,8,6,0,1,8,2,8,4,7,7,0,6,2,9,9,4,0,1,
%T A198143 0,4,9,8,7,2,7,9,3,8,2,1,9,3,0,3,1,4,4,1,9,0,0,1,4,4,4,4,4,2,3,9,5,3,
%U A198143 1,0,9,9,2,4,3,7,1,6,5,6,8,5,9,2,7,2,9,3,0,3,1,0,2,6,3,1,9,6,3
%N A198143 Decimal expansion of greatest x having x^2-3x=-3*cos(x).
%C A198143 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198143 least x: 0.89291071141777527373996831831704569...
%e A198143 greatest x: 3.69234777392798986018284770629940...
%t A198143 a = 1; b = -3; c = -3;
%t A198143 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198143 Plot[{f[x], g[x]}, {x, -1, 4}]
%t A198143 r1 = x /. FindRoot[f[x] == g[x], {x, 0.89, 0.90}, WorkingPrecision -> 110]
%t A198143 RealDigits[r1] (* A198142 *)
%t A198143 r2 = x /. FindRoot[f[x] == g[x], {x, 3.6, 3.7}, WorkingPrecision -> 110]
%t A198143 RealDigits[r2] (* A198143 *)
%Y A198143 Cf. A197737.
%K A198143 nonn,cons
%O A198143 1,1
%A A198143 _Clark Kimberling_, Oct 21 2011