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 A072223 #8 Feb 11 2025 10:55:35
%S A072223 5,2,4,8,8,8,5,9,8,6,5,6,4,0,4,7,9,3,8,9,9,4,8,6,1,3,8,5,4,1,2,8,3,9,
%T A072223 1,5,6,9,0,3,4,2,9,4,7,7,3,9,3,4,2,1,5,9,6,5,3,1,4,2,1,6,4,2,1,1,8,5,
%U A072223 8,0,6,8,6,5,8,4,4,4,4,1,7,2,6,2,5,4,9,2,1,0,9,1,7,6,1,3,1,1,2
%N A072223 Decimal expansion of unimodal analog of golden section with respect to A072176: a=lim A072176(n)/A072176(n+1).
%C A072223 This is the smallest real root of (1-x^2)^2=x.
%H A072223 <a href="/index/Al#algebraic_04">Index entries for algebraic numbers, degree 4</a>.
%e A072223 0.52488859865640479389948613854...
%t A072223 RealDigits[ x /. FindRoot[ (1-x^2)^2==x, {x, 0.5}, WorkingPrecision->100 ], 10 ][ [ 1 ] ]
%o A072223 (PARI) polrootsreal(x^4 - 2*x^2 - x + 1)[1] \\ _Charles R Greathouse IV_, Feb 11 2025
%Y A072223 Cf. A072176, A072224.
%K A072223 nonn,easy,cons
%O A072223 0,1
%A A072223 Michele Dondi (bik.mido(AT)tiscalinet.it), Jul 04 2002