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 A264562 #3 Nov 17 2015 18:06:04 %S A264562 1,15,888,84672,17444160,5356808640,2800372248576 %N A264562 Number of 3Xn arrays of permutations of 0..n*3-1 with rows nondecreasing modulo 2 and columns nondecreasing modulo 3. %C A264562 Row 3 of A264560. %e A264562 Some solutions for n=4 %e A264562 ..6..7..9..3....0.10..6..9....6.10..0..1....0.10..6..4....6..9..7..1 %e A264562 ..4.10..2..0....7..1..3.11....9..5..3..7....2.11..3..7....0..3.11..5 %e A264562 ..8..1..5.11....2..8..4..5....4..2..8.11....8..5..9..1...10..4..2..8 %Y A264562 Cf. A264560. %K A264562 nonn %O A264562 1,2 %A A264562 _R. H. Hardin_, Nov 17 2015