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A203456
Number of nX4 0..2 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors
1
1, 22, 543, 8837, 143936, 2527020, 44974778, 799146435, 14222292590, 253497958735, 4520112095307, 80604855648245, 1437506215952323, 25637856292628890, 457259186435170066, 8155419408921364692
OFFSET
1,2
COMMENTS
Column 4 of A203460
LINKS
EXAMPLE
Some solutions for n=5
..1..1..0..0....2..2..1..1....1..2..2..2....1..1..1..1....0..1..2..2
..1..2..2..1....2..2..1..1....1..2..0..2....1..2..2..2....1..1..2..2
..1..2..2..1....1..0..0..0....2..2..0..2....1..2..2..2....1..2..2..1
..2..2..1..0....2..2..0..0....2..1..2..2....2..2..1..1....0..2..2..0
..2..2..0..0....2..2..0..0....2..2..2..1....2..2..1..1....0..1..1..0
CROSSREFS
Sequence in context: A266884 A182610 A320766 * A271266 A333899 A239652
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 02 2012
STATUS
approved