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 A264644 #3 Nov 19 2015 13:53:57 %S A264644 1,1,8,55,572,5928,113808,2536688,79981184,2501785344,102724061184, %T A264644 4063172935680,228978765692928 %N A264644 Number of 2Xn arrays of permutations of 0..n*2-1 with rows nondecreasing modulo 3 and columns nondecreasing modulo 4. %C A264644 Row 2 of A264643. %e A264644 Some solutions for n=4 %e A264644 ..4..1..2..5....0..6..1..4....0..7..1..4....3..0..6..1....0..7..4..1 %e A264644 ..0..3..6..7....3..7..2..5....6..3..5..2....7..4..2..5....6..3..2..5 %Y A264644 Cf. A264643. %K A264644 nonn %O A264644 1,3 %A A264644 _R. H. Hardin_, Nov 19 2015