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A221730
Number of 4 X n 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
0, 44, 464, 6188, 80160, 1048566, 13757056, 180437354, 2363318964, 30930073844, 404584067882, 5290050421396
OFFSET
1,2
EXAMPLE
Some solutions for n=3:
..2..2..0....2..0..2....2..2..0....0..0..2....0..0..2....0..2..0....0..2..0
..0..2..0....2..0..0....0..0..2....2..2..0....2..2..2....2..0..2....0..0..2
..0..0..2....0..2..0....2..2..0....2..2..0....0..2..0....0..2..2....2..2..0
..2..2..0....2..2..0....0..2..0....0..0..2....0..0..2....0..0..2....2..0..2
CROSSREFS
Row 4 of A221728.
Sequence in context: A094201 A210426 A231242 * A306036 A160150 A210119
KEYWORD
nonn,more
AUTHOR
R. H. Hardin, Jan 22 2013
STATUS
approved