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 A231346 #12 Nov 08 2017 12:11:23 %S A231346 0,0,0,1,3,4,5,7,8,8,8,11,15,17,18,19,19,19,19,19,22 %N A231346 Number of distinct polygonal shapes after n-th stage in the structure of the D-toothpick cellular automaton of A220500. %C A231346 The cellular automaton of A220500 contains a large number of distinct polygonal shapes. The exact number is unknown. Apparently it's greater than 63. %C A231346 For simplicity we also call polygonal shapes "polygons". %C A231346 In order to construct this sequence we use the following rules: %C A231346 - Consider only the convex polygons and the concave polygons. Self-intersecting polygons are not counted. %C A231346 - Unfinished polygons with inward growth are not counted. %C A231346 - If two polygons have the same shape but they have different size then these polygons must be counted as distinct polygonal shapes. %C A231346 - The reflected shapes of asymmetric polygons, both with the same area, must be counted as distinct polygonal shapes. %C A231346 Question: Is there a maximal record in this sequence? %H A231346 Omar E. Pol, <a href="http://www.polprimos.com/imagenespub/poltp070.jpg">Illustration of the structure of A220500 after 17 stages</a>, (Contains 19 distinct polygonal shapes.) %H A231346 N. J. A. Sloane, <a href="/wiki/Catalog_of_Toothpick_and_CA_Sequences_in_OEIS">Catalog of Toothpick and Cellular Automata Sequences in the OEIS</a> %H A231346 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a> %Y A231346 Cf. A139250, A194276, A220500, A220512, A220514, A220520, A220522, A220524, A220526. %K A231346 nonn,hard,more %O A231346 1,5 %A A231346 _Omar E. Pol_, Dec 07 2013