cp's OEIS Frontend

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.

A341030 Decimal expansion of the perimeter of the convex hull around the dragon curve fractal.

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%I A341030 #12 Jun 28 2023 08:21:29
%S A341030 4,1,2,9,2,7,3,1,0,0,1,5,3,7,0,8,2,2,7,8,5,9,3,1,4,8,3,2,9,2,3,6,2,8,
%T A341030 0,5,4,7,7,7,2,3,7,8,1,6,1,3,8,2,6,3,8,3,1,0,2,9,8,0,3,7,5,8,4,3,4,4,
%U A341030 6,0,4,9,5,4,4,4,2,9,4,9,7,2,5,0,7,4,8,4,2,6,7,4,5,8,4,3,8,4,3,1,6,1,8,2,9
%N A341030 Decimal expansion of the perimeter of the convex hull around the dragon curve fractal.
%C A341030 Benedek and Panzone determine the 10 vertices of the polygon which is the convex hull around the dragon fractal.  The perimeter follows from these.
%H A341030 Kevin Ryde, <a href="/A341030/b341030.txt">Table of n, a(n) for n = 1..10000</a>
%H A341030 Agnes I. Benedek and Rafael Panzone, <a href="https://inmabb.criba.edu.ar/revuma/pdf/v39n1y2/p076-089.pdf">On Some Notable Plane Sets, II: Dragons</a>, Revista de la Unión Matemática Argentina, volume 39, numbers 1-2, 1994, pages 76-90.
%H A341030 Kevin Ryde, <a href="http://user42.tuxfamily.org/dragon/index.html">Iterations of the Dragon Curve</a>, see index "HBf".
%F A341030 Equals 3/2 + (5/6)*sqrt(2) + (1/6)*sqrt(13) + (1/6)*sqrt(26).
%F A341030 Equals 2/3 + (1 + sqrt(2))*(5 + sqrt(13))/6.
%F A341030 Largest root of 81*x^4 - 486*x^3 + 693*x^2 - 282*x + 17 = 0 (all its roots are real).
%e A341030 4.1292731001...
%t A341030 RealDigits[2/3 + (1 + Sqrt[2])*(5 + Sqrt[13])/6, 10, 120][[1]] (* _Amiram Eldar_, Jun 28 2023 *)
%Y A341030 Cf. A341029 (finite hull areas).
%K A341030 cons,nonn
%O A341030 1,1
%A A341030 _Kevin Ryde_, Feb 02 2021