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 A068271 #11 Jun 25 2017 17:11:43 %S A068271 1,12,264,11424,1008576,184910592,71033971200,57469424744448, %T A068271 98237339264864256,355574469749489123328,2729407814499050197254144, %U A068271 44482040254775494064841818112,1540473331004371306422199656382464,113440401780206156918876627438624833536 %N A068271 1/4 the number of colorings of an n X n rhombic hexagonal array with 4 colors. %C A068271 Terms for rhombic- and staggered- hexagonal arrays are the same for n in 1..4. %H A068271 Andrew Howroyd, <a href="/A068271/b068271.txt">Table of n, a(n) for n = 1..16</a> %Y A068271 Cf. A068239-A068305, A000332, A002417, A027441, A212162, A212163. %K A068271 nonn %O A068271 1,2 %A A068271 _R. H. Hardin_, Feb 24 2002 %E A068271 a(9) from _Alois P. Heinz_, May 02 2012 %E A068271 a(10)-a(14) from _Andrew Howroyd_, Jun 25 2017