login
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
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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 09 2013
STATUS
approved