A221331 Number of 4 X n arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2.

1, 577, 33873, 2460824, 162430981, 10794156688, 711858713069, 46910596287335, 3089778765626866, 203426990390736036, 13389504827335440162, 881130781309712234876, 57978558022828544235124, 3814742757245230038689495

Offset: 1

Author

R. H. Hardin, Jan 11 2013

Keywords

• nonn
• changed

Comments

Row 4 of A221328.

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..27

Crossrefs

Cf. A221328.