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 A198347 #7 Feb 07 2025 16:44:05
%S A198347 4,7,1,8,8,7,6,4,8,2,4,7,7,8,4,3,4,4,7,0,6,5,7,4,4,4,7,6,8,6,5,6,7,7,
%T A198347 7,7,4,8,1,0,2,9,8,7,6,0,7,2,2,7,0,7,9,4,3,0,5,8,8,1,6,6,0,0,5,9,1,2,
%U A198347 4,9,8,8,7,3,0,2,3,6,4,2,9,5,8,6,7,0,8,2,4,3,9,5,3,5,4,3,3,8,4
%N A198347 Decimal expansion of x>0 having 4*x^2=cos(x).
%C A198347 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198347 x=0.471887648247784344706574447686567777...
%t A198347 a = 4; b = 0; c = 1;
%t A198347 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198347 Plot[{f[x], g[x]}, {x, -1, 1}]
%t A198347 r = x /. FindRoot[f[x] == g[x], {x, .4, .5}, WorkingPrecision -> 110]
%t A198347 RealDigits[r] (* A198347 *)
%Y A198347 Cf. A197737.
%K A198347 nonn,cons
%O A198347 0,1
%A A198347 _Clark Kimberling_, Oct 23 2011