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A303889
Number of n X n 0..1 arrays with every element unequal to 1, 2, 3 or 4 king-move adjacent elements, with upper left element zero.
0
0, 7, 54, 1659, 29479, 1541443, 71307109, 5846922441, 668263785713, 103693982275562
OFFSET
1,2
COMMENTS
Diagonal of A303896.
EXAMPLE
Some solutions for n=5
..0..0..0..1..1. .0..1..1..1..0. .0..0..1..1..1. .0..1..1..0..1
..1..0..0..1..0. .0..0..1..1..1. .1..1..1..1..0. .0..1..1..1..0
..1..0..1..1..0. .0..0..0..0..0. .0..1..0..0..0. .1..1..1..0..0
..0..0..1..1..1. .1..0..0..0..0. .1..0..0..0..1. .0..1..0..0..0
..0..1..0..0..1. .0..1..0..1..1. .0..0..1..1..1. .1..0..0..0..1
CROSSREFS
Cf. A303896.
Sequence in context: A298104 A289865 A182124 * A198149 A203878 A043077
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 02 2018
STATUS
approved