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 A250301 #19 Jan 19 2015 20:34:34 %S A250301 0,3,3,6,12,12,6,12,18,18,18,18,36,36,12,24,30,18,18,24,42,54,42,36, %T A250301 60,66,54,48,90,90,30,54,54,18,18,24,42,54,42,42,66,78,78,78,114,150, %U A250301 102,72,108 %N A250301 First differences of A250300. %C A250301 Number of cells turned "ON" at n-th stage of cellular automaton of A250300. %C A250301 Compare A161645. %H A250301 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 A250301 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a> %e A250301 Positive terms can be written as a triangle in which row lengths is A011782 as shown below: %e A250301 3; %e A250301 3; %e A250301 6, 12; %e A250301 12, 6, 12, 18; %e A250301 18, 18, 18, 36, 36, 12, 24, 30; %e A250301 18, 18, 24, 42, 54, 42, 36, 60, 66, 54, 48, 90, 90, 30, 54, 54; %e A250301 18, 18, 24, 42, 54, 42, 42, 66, 78, 78, 78, 114, 150, 102, 72, 108, ... %Y A250301 Cf. A139251, A147582, A151724, A160121, A161645, A182633, A250300, A253771. %K A250301 nonn,tabf,more %O A250301 0,2 %A A250301 _Omar E. Pol_, Jan 17 2015