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 A068280 #9 May 02 2012 12:10:51 %S A068280 1,1452,214360212,3217625521859892,4910668309995799841810892, %T A068280 762007921240709867578673020749884172, %U A068280 12022427131636998562079732651101772918046821260092,19285841951971298297383495940474744273219471204301574972512789012 %N A068280 1/13 times the number of colorings of an n X n rhombic hexagonal array with 13 colors. %C A068280 Terms for rhombic- and staggered- hexagonal arrays are the same for n in 1..4. %Y A068280 Cf. A068239-A068305, A000332, A002417, A027441, A212162, A212163. %K A068280 nonn %O A068280 1,2 %A A068280 _R. H. Hardin_, Feb 24 2002 %E A068280 a(5)-a(8) from _Alois P. Heinz_, May 02 2012