A221729 Number of 3Xn arrays of occupancy after each element stays put or moves to some horizontal, diagonal or antidiagonal neighbor, with every occupancy equal to zero or two.

0, 16, 0, 540, 0, 22180, 0, 911081, 0, 37357844, 0, 1530451369, 0, 62678117602, 0, 2566608259733, 0, 105095354454990, 0, 4303284726664321, 0, 176203240002820998, 0, 7214839389152381265, 0, 295419432979789366510, 0, 12096265452242634926017

Offset: 1

Author

R. H. Hardin Jan 22 2013

Keywords

• nonn

Comments

Row 3 of A221728

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..32