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 A198130 #6 Feb 07 2025 16:44:04
%S A198130 1,5,2,7,9,9,9,7,1,2,0,3,6,8,4,0,6,3,3,5,2,0,8,3,6,6,9,3,8,8,8,9,0,4,
%T A198130 6,6,3,6,7,6,3,7,5,9,3,9,9,4,1,6,2,5,9,9,2,0,8,7,2,7,8,7,3,2,5,4,0,3,
%U A198130 7,9,1,6,5,3,5,9,8,1,0,2,5,1,2,5,7,5,0,2,9,4,2,8,6,0,8,7,8,9,6
%N A198130 Decimal expansion of least x having 2*x^2+3x=2*cos(x).
%C A198130 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198130 least x: -1.52799971203684063352083669388890466...
%e A198130 greatest x: 0.458061086830838048904156490023125...
%t A198130 a = 2; b = 3; c = 2;
%t A198130 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198130 Plot[{f[x], g[x]}, {x, -2, 1}]
%t A198130 r1 = x /. FindRoot[f[x] == g[x], {x, -1.53, -1.52}, WorkingPrecision -> 110]
%t A198130 RealDigits[r1](* A198130 *)
%t A198130 r2 = x /. FindRoot[f[x] == g[x], {x, .45, .46}, WorkingPrecision -> 110]
%t A198130 RealDigits[r2](* A198131 *)
%Y A198130 Cf. A197737.
%K A198130 nonn,cons
%O A198130 1,2
%A A198130 _Clark Kimberling_, Oct 22 2011