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 A198137 #6 Feb 07 2025 16:44:05
%S A198137 2,4,7,6,6,1,6,9,7,4,0,6,6,8,1,7,0,8,1,0,1,9,2,7,2,6,4,1,7,3,2,2,4,7,
%T A198137 7,4,8,4,0,2,1,0,1,7,7,8,4,7,1,8,8,6,3,1,2,1,4,1,4,7,7,7,8,9,2,1,6,0,
%U A198137 7,4,0,2,1,6,0,6,7,7,5,5,2,1,6,4,6,7,3,7,0,4,4,9,7,2,1,9,4,1,4
%N A198137 Decimal expansion of greatest x having 2*x^2-4x=-3*cos(x).
%C A198137 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198137 least x: 0.85876971369761442119310432181053308611...
%e A198137 greatest x: 2.4766169740668170810192726417322477...
%t A198137 a = 2; b = -4; c = -3;
%t A198137 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198137 Plot[{f[x], g[x]}, {x, -1, 3}]
%t A198137 r1 = x /. FindRoot[f[x] == g[x], {x, .85, .86}, WorkingPrecision -> 110]
%t A198137 RealDigits[r1] (* A198136 *)
%t A198137 r2 = x /. FindRoot[f[x] == g[x], {x, 2.4, 2.5}, WorkingPrecision -> 110]
%t A198137 RealDigits[r2] (* A198137 *)
%Y A198137 Cf. A197737.
%K A198137 nonn,cons
%O A198137 1,1
%A A198137 _Clark Kimberling_, Oct 22 2011