A268157 Number of n X 3 arrays containing 3 copies of 0..n-1 with every element equal to at least one vertical or antidiagonal neighbor and the top left element equal to 0.

0, 1, 8, 36, 456, 6360, 93600, 1784160, 38102400, 899579520, 23960966400, 699741504000

Offset: 1

Author

R. H. Hardin, Jan 27 2016

Keywords

• nonn

Comments

Column 3 of A268159.

Examples

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

Crossrefs

Cf. A268159.