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 A253767 #29 Dec 31 2020 11:11:15 %S A253767 1,8,15,40,47,96,121,224,231,280,329,504,529,704,807,1216,1223,1272, %T A253767 1321,1496,1545,1888,2063,2784,2809,2984,3159,3784,3887,4608,5017, %U A253767 6656,6663,6712,6761,6936,6985,7328,7503,8224,8273,8616,8959,10184,10359,11584,12305,15168,15193,15368,15543,16168 %N A253767 Partial sums of A247666. %C A253767 Also, total number of ON cells after n generations in a three-dimensional cellular automaton where A247666(n) gives the number of ON cells in the n-th level of the structure starting from the top. An ON cell remains ON forever. An ON cell is an hexagonal prism of height 1. We start with a single ON cell. The structure looks like an irregular stepped pyramid, apparently with a like-hexagonal base. %H A253767 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 A253767 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a> %Y A253767 Cf. A116520, A245542, A247666, A253908. %K A253767 nonn %O A253767 0,2 %A A253767 _Omar E. Pol_, Jan 29 2015