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 A198357 #6 Feb 07 2025 16:44:05
%S A198357 7,4,6,0,7,4,3,6,2,1,2,8,5,6,4,4,6,1,7,3,2,5,7,4,1,8,9,8,5,6,5,3,0,6,
%T A198357 7,3,5,6,8,5,1,9,0,1,4,6,8,5,0,2,7,8,5,6,9,0,8,2,2,9,6,4,8,7,6,6,2,2,
%U A198357 9,3,3,0,9,6,2,0,1,6,5,1,3,7,8,3,6,3,0,2,6,7,3,7,8,0,4,5,1,1,2
%N A198357 Decimal expansion of least x having 4*x^2+2x=cos(x).
%C A198357 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198357 least x: -0.7460743621285644617325741898565306735...
%e A198357 greatest x: 0.29900587455031735703746835072454193932...
%t A198357 a = 4; b = 2; c = 1;
%t A198357 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198357 Plot[{f[x], g[x]}, {x, -1, 1}]
%t A198357 r1 = x /. FindRoot[f[x] == g[x], {x, -.8, -.7}, WorkingPrecision -> 110]
%t A198357 RealDigits[r1] (* A198357 *)
%t A198357 r2 = x /. FindRoot[f[x] == g[x], {x, .29, .30}, WorkingPrecision -> 110]
%t A198357 RealDigits[r2] (* A198358 *)
%Y A198357 Cf. A197737.
%K A198357 nonn,cons
%O A198357 0,1
%A A198357 _Clark Kimberling_, Oct 24 2011