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 A198349 #9 Feb 07 2025 16:44:05
%S A198349 5,9,6,6,2,8,6,9,4,8,2,8,1,2,2,2,0,9,7,7,2,0,7,1,5,5,3,4,8,4,9,6,6,0,
%T A198349 8,8,1,7,4,2,1,7,7,5,4,0,6,1,7,2,3,8,8,0,0,6,4,3,6,0,0,9,1,7,8,3,5,1,
%U A198349 5,9,5,6,7,8,7,3,4,9,2,3,6,7,4,7,5,1,2,9,3,3,8,8,6,4,2,4,8,4,9,5,6,6,5,5
%N A198349 Decimal expansion of least x having 4*x^2+x=cos(x).
%C A198349 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198349 least x: -0.596628694828122209772071553484966...
%e A198349 greatest x: 0.3733959160193969688968321519818...
%t A198349 a = 4; b = 1; c = 1;
%t A198349 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198349 Plot[{f[x], g[x]}, {x, -1, 1}]
%t A198349 r1 = x /. FindRoot[f[x] == g[x], {x, -.6, -.5}, WorkingPrecision -> 110]
%t A198349 RealDigits[r1] (* A198349 *)
%t A198349 r2 = x /. FindRoot[f[x] == g[x], {x, .37, .38}, WorkingPrecision -> 110]
%t A198349 RealDigits[r2] (* A198350 *)
%Y A198349 Cf. A197737.
%K A198349 nonn,cons
%O A198349 0,1
%A A198349 _Clark Kimberling_, Oct 23 2011