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 A198840 #10 Feb 07 2025 16:44:05
%S A198840 1,6,4,4,6,4,7,2,7,4,3,1,3,4,6,2,7,1,7,7,1,4,6,4,2,3,2,5,5,6,8,1,5,9,
%T A198840 2,4,6,7,0,5,8,7,0,1,4,1,3,4,1,8,6,0,7,1,5,0,7,2,8,0,1,8,6,7,6,3,9,9,
%U A198840 6,8,8,5,4,0,8,5,6,3,4,9,7,8,2,1,7,1,1,6,4,8,5,9,3,7,8,5,6,5,2
%N A198840 Decimal expansion of x > 0 satisfying x^2 - 4*cos(x) = 3.
%C A198840 See A198755 for a guide to related sequences. The Mathematica program includes a graph.
%H A198840 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A198840 1.644647274313462717714642325568159246705870...
%t A198840 a = 1; b = -4; c = 3;
%t A198840 f[x_] := a*x^2 + b*Cos[x]; g[x_] := c
%t A198840 Plot[{f[x], g[x]}, {x, -3, 3}, {AxesOrigin -> {0, 0}}]
%t A198840 r = x /. FindRoot[f[x] == g[x], {x, 1.6, 1.65}, WorkingPrecision -> 110]
%t A198840 RealDigits[r] (* A198840 *)
%Y A198840 Cf. A198755.
%K A198840 nonn,cons
%O A198840 1,2
%A A198840 _Clark Kimberling_, Oct 30 2011
%E A198840 Offset corrected by _Georg Fischer_, Aug 05 2021