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 A197841 #6 Feb 07 2025 16:44:04
%S A197841 1,8,5,0,7,1,7,4,4,1,5,6,1,9,8,2,9,0,1,2,9,7,8,7,8,8,3,1,4,5,8,8,7,4,
%T A197841 4,9,2,3,9,5,6,3,3,6,9,1,3,7,1,4,2,8,7,9,1,6,1,7,6,9,7,0,2,3,2,0,9,6,
%U A197841 1,4,6,7,3,5,0,9,4,6,9,2,9,6,0,2,4,5,4,8,8,9,3,2,3,3,7,3,4,3,2
%N A197841 Decimal expansion of least x having x^2+2x=cos(x).
%C A197841 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A197841 least x: -1.85071744156198290129787883145887449239...
%e A197841 greatest x: 0.38772212025498533427185200524832923...
%t A197841 a = 1; b = 2; c = 1;
%t A197841 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A197841 Plot[{f[x], g[x]}, {x, -2, 1}]
%t A197841 r1 = x /. FindRoot[f[x] == g[x], {x, -1.9, -1.8}, WorkingPrecision -> 110]
%t A197841 RealDigits[r1] (* A197841 *)
%t A197841 r2 = x /. FindRoot[f[x] == g[x], {x, .38, .39}, WorkingPrecision -> 110]
%t A197841 RealDigits[r2] (* A197842 *)
%Y A197841 Cf. A197737.
%K A197841 nonn,cons
%O A197841 1,2
%A A197841 _Clark Kimberling_, Oct 20 2011