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 A198369 #6 Feb 07 2025 16:44:05
%S A198369 1,1,0,2,3,8,4,7,4,6,2,7,9,4,3,9,5,9,5,8,0,5,8,1,8,3,6,5,8,6,7,8,8,1,
%T A198369 3,9,4,4,9,1,9,2,4,8,4,6,4,3,3,1,7,4,9,1,7,4,3,6,5,7,0,7,8,7,4,1,5,7,
%U A198369 9,8,0,2,0,1,8,1,3,2,9,9,5,9,2,5,9,7,1,9,5,8,2,4,5,4,1,1,4,7,8
%N A198369 Decimal expansion of least x having 4*x^2+4x=cos(x).
%C A198369 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198369 least x: -1.1023847462794395958058183658678813...
%e A198369 greatest x: 0.203451325531925041555116805060611...
%t A198369 a = 4; b = 4; c = 1;
%t A198369 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198369 Plot[{f[x], g[x]}, {x, -2, 1}]
%t A198369 r1 = x /. FindRoot[f[x] == g[x], {x, -1.2, -1.1}, WorkingPrecision -> 110]
%t A198369 RealDigits[r1] (* A198369 *)
%t A198369 r2 = x /. FindRoot[f[x] == g[x], {x, .20, .21}, WorkingPrecision -> 110]
%t A198369 RealDigits[r2] (* A198370 *)
%Y A198369 Cf. A197737.
%K A198369 nonn,cons
%O A198369 1,4
%A A198369 _Clark Kimberling_, Oct 24 2011