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 A264819 #3 Nov 25 2015 21:47:57 %S A264819 1,1,8,44,348,3946,52524,1041936,22648272,828481536,26112652416, %T A264819 1017144989568,50591916092160 %N A264819 Number of 2Xn arrays of permutations of 0..n*2-1 with rows nondecreasing modulo 3 and columns nondecreasing modulo 7. %C A264819 Row 2 of A264818. %e A264819 Some solutions for n=7 %e A264819 ..3..9..0..1..7.11..8...12..9..3..0..7.11..8...12..3..0..9..4..1..7 %e A264819 .12..6.13.10..4..5..2....6.13.10..1..4..5..2....6.13.10..5.11..8..2 %Y A264819 Cf. A264818. %K A264819 nonn %O A264819 1,3 %A A264819 _R. H. Hardin_, Nov 25 2015