A266570 Number of nX2 arrays containing 2 copies of 0..n-1 with no element 1 greater than its northwest or southwest neighbor modulo n and the upper left element equal to 0.

1, 1, 5, 74, 2668, 150836, 12011058, 1279437414, 175836809388, 30308775142980, 6404886614932128

Offset: 1

Author

R. H. Hardin, Jan 01 2016

Keywords

• nonn

Comments

Column 2 of A266572.

Examples

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

Crossrefs

Cf. A266572.