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 A242129 #14 Jun 17 2019 04:20:41 %S A242129 5,5,10,15,20,25,40,30,30,45,60,55,65,55,70,75,90,75,90 %N A242129 Number of tiles added in each step if a centrally symmetric Penrose rhomb tiling, beginning with a central 'Sun' configuration, is successively extended in steps as defined below. %C A242129 In each step, add a new tile to each free edge of the current tiling. The first step is the placement of the five central tiles. %H A242129 David Austin, <a href="http://www.ams.org/publicoutreach/feature-column/fcarc-penrose">Penrose tiles talk across miles</a>, AMS Feature Column, August 2005. %H A242129 Felix Fröhlich, <a href="/A242129/a242129.pdf">Layers in the Penrose rhomb tiling with a "Sun" patch as a center of global fivefold rotational symmetry</a>, 2019. %H A242129 Wikipedia, <a href="https://en.wikipedia.org/wiki/Penrose_tiling">Penrose tiling</a> %e A242129 See illustrations in Fröhlich, 2019. %Y A242129 Cf. A242128 (5-fold, Star), A242888 (7-fold, Star), A242889 (7-fold, Sun), A242890 (8-fold, Star), A242891 (8-fold, Sun), A242892 (9-fold, Star), A242893 (9-fold, Sun), A242894 (Kite and dart, Star), A242895 (Kite and dart, Sun). %K A242129 nonn,more %O A242129 1,1 %A A242129 _Felix Fröhlich_, May 05 2014 %E A242129 a(8)-a(19) from _Felix Fröhlich_, Jun 16 2019