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 A338097 #17 Oct 13 2020 15:44:01 %S A338097 0,2,4,8,12,18,22,28,32,36,44,56,76,86,100,116,130,144,164,178,198, %T A338097 218,242,260,282,306,350,386,414,446,460,484,516,556,586,638,688,736, %U A338097 770,800,828,872,914,964,1012,1068,1122,1162,1204,1252,1300,1360,1408,1462 %N A338097 Number of ON cells after n generations of cellular automaton based on a hexagonal grid and starting with two adjacent ON cells where an OFF cell is turned ON if exactly two of its six neighbors are ON. %C A338097 An ON cell remains ON forever. %H A338097 Rémy Sigrist, <a href="/A338097/b338097.txt">Table of n, a(n) for n = 0..8192</a> %H A338097 Rémy Sigrist, <a href="/A338098/a338098_1.png">Illustration of initial terms</a> %H A338097 Rémy Sigrist, <a href="/A338097/a338097.png">Illustration of the structure at generation 512</a> %H A338097 Rémy Sigrist, <a href="/A338097/a338097.gp.txt">PARI program for A338097</a> %H A338097 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a> %o A338097 (PARI) See Links section. %Y A338097 Cf. A151731 (square grid variant), A338098. %K A338097 nonn %O A338097 0,2 %A A338097 _Rémy Sigrist_, Oct 10 2020