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 A198839 #10 Feb 07 2025 16:44:05
%S A198839 1,5,0,4,7,1,0,1,0,6,8,5,0,9,4,5,4,9,9,7,7,7,2,5,1,4,4,9,0,7,7,7,0,9,
%T A198839 6,5,7,1,8,8,8,5,9,0,3,7,4,3,3,2,3,4,8,1,9,6,2,5,1,3,3,0,5,9,3,6,0,9,
%U A198839 0,3,1,2,1,0,4,8,3,9,0,9,7,4,9,7,7,4,2,5,6,8,0,3,4,3,3,6,9,7,0,8,9
%N A198839 Decimal expansion of x>0 satisfying x^2-4*cos(x)=2.
%C A198839 See A198755 for a guide to related sequences. The Mathematica program includes a graph.
%H A198839 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A198839 1.5047101068509454997772514490777096571888...
%t A198839 a = 1; b = -4; c = 2;
%t A198839 f[x_] := a*x^2 + b*Cos[x]; g[x_] := c
%t A198839 Plot[{f[x], g[x]}, {x, -3, 3}, {AxesOrigin -> {0, 0}}]
%t A198839 r = x /. FindRoot[f[x] == g[x], {x, 1.5, 1.51}, WorkingPrecision -> 110]
%t A198839 RealDigits[r] (* A198839 *)
%Y A198839 Cf. A198755.
%K A198839 nonn,cons
%O A198839 1,2
%A A198839 _Clark Kimberling_, Oct 30 2011