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 A200021 #11 Feb 12 2025 04:58:23
%S A200021 1,4,7,6,3,6,8,7,4,8,3,8,0,9,2,0,3,9,1,6,7,1,6,9,6,8,8,9,7,8,9,8,3,6,
%T A200021 4,1,6,4,3,6,9,3,2,3,2,3,1,9,7,3,2,4,9,9,3,0,3,6,9,4,0,4,4,5,3,9,6,6,
%U A200021 8,4,3,0,8,6,1,5,8,0,7,6,0,1,2,4,0,6,0,1,7,3,0,4,8,3,3,6,9,6,2
%N A200021 Decimal expansion of greatest x satisfying x^2 - 2*cos(x) = 2*sin(x).
%C A200021 See A199949 for a guide to related sequences. The Mathematica program includes a graph.
%H A200021 G. C. Greubel, <a href="/A200021/b200021.txt">Table of n, a(n) for n = 1..10000</a>
%H A200021 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A200021 least x: -0.64004919114257711573983526967584120...
%e A200021 greatest x: 1.4763687483809203916716968897898364...
%t A200021 a = 1; b = -2; c = 2;
%t A200021 f[x_] := a*x^2 + b*Cos[x]; g[x_] := c*Sin[x]
%t A200021 Plot[{f[x], g[x]}, {x, -1, 2}, {AxesOrigin -> {0, 0}}]
%t A200021 r = x /. FindRoot[f[x] == g[x], {x, -.65, -.64}, WorkingPrecision -> 110]
%t A200021 RealDigits[r] (* A200020 *)
%t A200021 r = x /. FindRoot[f[x] == g[x], {x, 1.47, 1.48}, WorkingPrecision -> 110]
%t A200021 RealDigits[r] (* A200021 *)
%o A200021 (PARI) a=1; b=-2; c=2; solve(x=1, 2, a*x^2 + b*cos(x) - c*sin(x)) \\ _G. C. Greubel_, Jun 24 2018
%Y A200021 Cf. A199949.
%K A200021 nonn,cons
%O A200021 1,2
%A A200021 _Clark Kimberling_, Nov 12 2011