A221727 Number of nX4 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

4, 52, 540, 6188, 71310, 824144, 9525048, 110070012, 1271809066, 14694217628, 169767833676, 1961352594276, 22659537510670, 261784302805272, 3024367348612856, 34940131867655732, 403658398327592910

Offset

1,1

Comments

Column 4 of A221728

Links

R. H. Hardin, Table of n, a(n) for n = 1..29

Example

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

Crossrefs

Sequence in context: A229146 A071953 A247746 * A144339 A155661 A198281

Adjacent sequences: A221724 A221725 A221726 * A221728 A221729 A221730

Keyword

nonn

Author

R. H. Hardin Jan 22 2013

Status

approved