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 A264640 #3 Nov 19 2015 07:29:43 %S A264640 1,16,960,107568,21565440,10027929600,7163873280000 %N A264640 Number of 3Xn arrays of permutations of 0..n*3-1 with rows nondecreasing modulo 2 and columns nondecreasing modulo 4. %C A264640 Row 3 of A264638. %e A264640 Some solutions for n=4 %e A264640 ..0..4..6..8....8..6..0..1....4..2..8..1....8..4..9..1....0..8..5..1 %e A264640 ..2..1.11..9....4..2..5..9....0..6.10..9....0..6.10..5....4..6.10..9 %e A264640 .10..5..3..7...10..7.11..3...11..3..7..5....2..7.11..3....2..7.11..3 %Y A264640 Cf. A264638. %K A264640 nonn %O A264640 1,2 %A A264640 _R. H. Hardin_, Nov 19 2015