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 A264660 #3 Nov 20 2015 07:27:44 %S A264660 1,3,16,148,2400,62800,2150784,89051520,4376959488,264110948352 %N A264660 Number of 2Xn arrays of permutations of 0..n*2-1 with rows nondecreasing modulo 2 and columns nondecreasing modulo 5. %C A264660 Row 2 of A264659. %e A264660 Some solutions for n=5 %e A264660 ..2..0..6..5..1....0..7..9..1..5....0..8..1..7..5....2..0..5..3..1 %e A264660 ..8..4..3..9..7....2..8..4..6..3....2..4..6..3..9....4..6..8..9..7 %Y A264660 Cf. A264659. %K A264660 nonn %O A264660 1,2 %A A264660 _R. H. Hardin_, Nov 20 2015