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 A264730 #3 Nov 22 2015 11:03:02 %S A264730 1,3,48,663,23096,1602048,165778944,13350330368 %N A264730 Number of 3Xn arrays of permutations of 0..n*3-1 with rows nondecreasing modulo 4 and columns nondecreasing modulo 6. %C A264730 Row 3 of A264728. %e A264730 Some solutions for n=5 %e A264730 .12..0..2.14..6....8.12..0..6..7....0.12.13..1..7....0.12..1..6..2 %e A264730 ..8.13..9..5..7....4.13..1..2..3...10..6.14..2..3....8..9.13..7..3 %e A264730 ..4..1.10.11..3....5..9.14.10.11....4..8..9..5.11....4..5.10.14.11 %Y A264730 Cf. A264728. %K A264730 nonn %O A264730 1,2 %A A264730 _R. H. Hardin_, Nov 22 2015