A264636 Number of nX2 arrays of permutations of 0..n*2-1 with rows nondecreasing modulo 2 and columns nondecreasing modulo 4.

1, 3, 16, 128, 1152, 12960, 269568, 6635520, 165888000, 4561920000, 209018880000, 10480803840000, 513559388160000, 26454892584960000, 2106067546275840000

Offset: 1

Author

R. H. Hardin, Nov 19 2015

Keywords

• nonn

Comments

Column 2 of A264638.

Examples

			Some solutions for n=4
..4..0....0..1....0..4....0..2....4..1....4..0....4..0....0..5....0..1....4..0
..2..1....4..5....1..5....4..6....0..6....2..5....5..1....4..1....4..5....1..5
..6..5....2..7....2..6....5..3....5..7....6..1....2..6....6..2....6..2....2..3
..3..7....6..3....3..7....1..7....2..3....7..3....3..7....3..7....3..7....6..7
		

Crossrefs

Cf. A264638.