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 A177241 #7 Sep 26 2015 01:17:11 %S A177241 0,1,4,4,16,4,16 %N A177241 First differences of A177240. %C A177241 Question: Is this the same as A102376 but starting with zero? (See also the main question in the entry A177240). %H A177241 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 A177241 <a href="/index/To#toothpick">Index entries for sequences related to toothpick sequences</a> %Y A177241 Cf. A102376, A116520, A139250, A139251, A160121. %K A177241 more,nonn %O A177241 0,3 %A A177241 _Omar E. Pol_, May 05 2010