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 A182798 #19 Aug 01 2023 15:00:00 %S A182798 4,24,192,2112,32640,718080,22665216,1031276544,67849629696, %T A182798 6468240187392,894839431299072,179851071814434816, %U A182798 52561241074964496384,22351071118387029737472,13837189739906569661841408 %N A182798 Number of 4-colorings of the n X n X n triangular grid. %C A182798 The n X n X n triangular grid has n rows with k vertices in row k. Each vertex is connected to the neighbors in the same row and up to two vertices in each of the neighboring rows. The graph has A000217(n) vertices and 3*A000217(n-1) edges altogether. %H A182798 Wikipedia, <a href="https://en.wikipedia.org/wiki/Chromatic_polynomial">Chromatic polynomial</a> %H A182798 Wikipedia, <a href="https://en.wikipedia.org/wiki/Lattice_graph#Other_kinds">Triangular grid graph</a> %F A182798 a(n) = 4 * A153467(n). %Y A182798 4th row of A182797. Cf. A178435, A182788, A182789, A182790, A182791, A182792, A182793, A182794, A182795, A182796. %K A182798 nonn %O A182798 1,1 %A A182798 _Alois P. Heinz_, Dec 02 2010 %E A182798 a(15) from _Alois P. Heinz_, Mar 11 2016