A221306 Number of nX4 arrays of occupancy after each element moves to some horizontal, vertical or antidiagonal neighbor, with every occupancy equal to zero or two

1, 31, 312, 3334, 38146, 431474, 4855258, 54587829, 613235478, 6885012344, 77275657244, 867163601744, 9729984671155, 109168050158528, 1224793149317547, 13741066811792010, 154160315091605934, 1729503583940965893

Offset

1,2

Comments

Column 4 of A221308

Links

R. H. Hardin, Table of n, a(n) for n = 1..39

Example

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

Crossrefs

Sequence in context: A212235 A126552 A068813 * A142382 A137318 A182025

Adjacent sequences: A221303 A221304 A221305 * A221307 A221308 A221309

Keyword

nonn

Author

R. H. Hardin Jan 09 2013

Status

approved