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 A198838 #8 Feb 07 2025 16:44:05
%S A198838 1,3,5,8,0,9,2,3,4,9,7,9,6,9,3,5,9,1,5,2,2,9,3,4,4,7,8,2,9,4,8,7,3,2,
%T A198838 1,8,3,3,8,3,9,9,6,9,6,0,5,6,2,0,9,2,1,9,2,8,5,9,0,0,7,8,6,1,2,0,3,9,
%U A198838 1,1,8,7,3,4,6,8,2,7,7,9,1,2,0,2,0,7,7,2,7,5,8,6,3,6,8,4,6,4,1
%N A198838 Decimal expansion of x>0 satisfying x^2-4*cos(x)=1.
%C A198838 See A198755 for a guide to related sequences. The Mathematica program includes a graph.
%H A198838 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A198838 1.358092349796935915229344782948732183383...
%t A198838 a = 1; b = -4; c = 1;
%t A198838 f[x_] := a*x^2 + b*Cos[x]; g[x_] := c
%t A198838 Plot[{f[x], g[x]}, {x, -3, 3}, {AxesOrigin -> {0, 0}}]
%t A198838 r = x /. FindRoot[f[x] == g[x], {x, 1.3, 1.4}, WorkingPrecision -> 110]
%t A198838 RealDigits[r] (* A198838 *)
%Y A198838 Cf. A198755.
%K A198838 nonn,cons
%O A198838 1,2
%A A198838 _Clark Kimberling_, Oct 30 2011