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 A198131 #6 Feb 07 2025 16:44:04
%S A198131 4,5,8,0,6,1,0,8,6,8,3,0,8,3,8,0,4,8,9,0,4,1,5,6,4,9,0,0,2,3,1,2,5,5,
%T A198131 1,2,7,0,2,4,9,8,7,8,6,0,0,9,3,5,4,9,1,0,7,2,4,6,7,3,8,6,2,7,8,9,3,1,
%U A198131 6,8,3,4,2,1,8,1,7,8,3,0,4,3,6,0,4,6,3,6,2,8,4,6,3,6,3,6,6,3,6
%N A198131 Decimal expansion of greatest x having 2*x^2+3x=2*cos(x).
%C A198131 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198131 least x: -1.52799971203684063352083669388890466...
%e A198131 greatest x: 0.458061086830838048904156490023125512...
%t A198131 a = 2; b = 3; c = 2;
%t A198131 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198131 Plot[{f[x], g[x]}, {x, -2, 1}]
%t A198131 r1 = x /. FindRoot[f[x] == g[x], {x, -1.53, -1.52}, WorkingPrecision -> 110]
%t A198131 RealDigits[r1](* A198130 *)
%t A198131 r2 = x /. FindRoot[f[x] == g[x], {x, .45, .46}, WorkingPrecision -> 110]
%t A198131 RealDigits[r2](* A198131 *)
%Y A198131 Cf. A197737.
%K A198131 nonn,cons
%O A198131 0,1
%A A198131 _Clark Kimberling_, Oct 22 2011