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 A229977 #18 Feb 16 2025 08:33:20 %S A229977 1,1,1,1,2,2,2,2,3,3,4,4,5,5,6,7,7,8,10,11,12,14,16,18,20,23,26,30,34, %T A229977 38,43,49,56,63,72,81,92,105,119,134,152,173,196,222,252,286,324,367, %U A229977 416,472,535,607,688,780,885,1003 %N A229977 Gosper island perimeter (rounded to the nearest integer) after n iterations, let starting perimeter = 1. %C A229977 The Gosper island curve bounds the space filled by the Peano-Gosper curve. The length of Peano-Gosper curve after n iterations (rounded to the nearest integer) is A017926(n) and the total number of elements is A000420(n). See illustration in links. %C A229977 The sequence expansion ratio (a(n)/a(n-1)) is 1.133893419... which is 3*A020764. %H A229977 Kival Ngaokrajang, <a href="/A229977/a229977.pdf">Illustration of initial terms</a> %H A229977 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GosperIsland.html">Gosper Island</a> %F A229977 a(n) = round((3/sqrt(7))^n). %Y A229977 Cf. A017926, A000420, A227381 (Koch snowflake perimeter). %K A229977 nonn %O A229977 0,5 %A A229977 _Kival Ngaokrajang_, Oct 05 2013