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 A198368 #6 Feb 07 2025 16:44:05
%S A198368 6,0,6,0,7,7,7,8,3,6,4,8,6,2,6,4,5,3,6,6,5,7,9,7,7,5,7,9,9,0,5,6,2,9,
%T A198368 1,0,5,7,8,9,9,1,3,1,8,1,7,8,8,5,7,2,2,2,5,3,4,2,4,7,5,8,6,3,2,8,9,9,
%U A198368 8,4,2,0,5,8,9,6,2,9,7,9,1,6,6,8,0,4,3,0,9,4,1,8,4,6,8,0,6,3,2
%N A198368 Decimal expansion of greatest x having 4*x^2+3x=4*cos(x).
%C A198368 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198368 least x: -1.128864420523986139477004663061889573...
%e A198368 greatest x: 0.60607778364862645366579775799056291...
%t A198368 a = 4; b = 3; c = 4;
%t A198368 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198368 Plot[{f[x], g[x]}, {x, -2, 1}]
%t A198368 r1 = x /. FindRoot[f[x] == g[x], {x, -1.2, -1.1}, WorkingPrecision -> 110]
%t A198368 RealDigits[r1] (* A198367 *)
%t A198368 r2 = x /. FindRoot[f[x] == g[x], {x, .60, .61}, WorkingPrecision -> 110]
%t A198368 RealDigits[r2] (* A198368 *)
%Y A198368 Cf. A197737.
%K A198368 nonn,cons
%O A198368 0,1
%A A198368 _Clark Kimberling_, Oct 24 2011