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 A068273 #12 Jun 25 2017 17:10:59 %S A068273 1,80,65600,552093440,47694893373440,42294602754348892160, %T A068273 384991688574716612134952960,35972520655083241381477879725916160, %U A068273 34501934082562716587411029908821592862883840,339679276508747763623945195020701159657032777565470720 %N A068273 1/6 the number of colorings of an n X n rhombic hexagonal array with 6 colors. %C A068273 Terms for rhombic- and staggered- hexagonal arrays are the same for n in 1..4. %Y A068273 Cf. A068239-A068305, A000332, A002417, A027441, A212162, A212163. %K A068273 nonn %O A068273 1,2 %A A068273 _R. H. Hardin_, Feb 24 2002 %E A068273 a(7)-a(9) from _Alois P. Heinz_, May 02 2012 %E A068273 a(10) from _Andrew Howroyd_, Jun 25 2017