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 A198356 #6 Feb 07 2025 16:44:05
%S A198356 7,4,2,4,3,7,4,8,8,9,6,5,6,0,3,3,7,8,5,1,7,2,4,5,5,3,0,1,6,4,3,2,6,3,
%T A198356 5,3,2,0,2,8,5,6,2,4,8,9,8,5,8,2,2,6,9,0,9,3,8,1,9,4,5,2,2,9,3,3,6,2,
%U A198356 8,9,1,7,9,5,7,6,0,6,0,6,8,0,2,1,5,9,5,3,1,4,5,8,7,7,4,9,8,8
%N A198356 Decimal expansion of greatest x having 4*x^2+x=4*cos(x).
%C A198356 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198356 least x: -0.91555432657358705292706966750136951...
%e A198356 greatest x: 0.7424374889656033785172455301643263...
%t A198356 a = 4; b = 1; c = 4;
%t A198356 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198356 Plot[{f[x], g[x]}, {x, -1, 1}]
%t A198356 r1 = x /. FindRoot[f[x] == g[x], {x, -1, -.9}, WorkingPrecision -> 110]
%t A198356 RealDigits[r1] (* A198355 *)
%t A198356 r2 = x /. FindRoot[f[x] == g[x], {x, .74, .75}, WorkingPrecision -> 110]
%t A198356 RealDigits[r2] (* A198356 *)
%Y A198356 Cf. A197737.
%K A198356 nonn,cons
%O A198356 0,1
%A A198356 _Clark Kimberling_, Oct 24 2011