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A304670
Number of n X n 0..1 arrays with every element unequal to 0, 2, 3, 5 or 6 king-move adjacent elements, with upper left element zero.
0
1, 4, 13, 56, 897, 20932, 930123, 73484449, 11082127004, 2811843090472
OFFSET
1,2
COMMENTS
Diagonal of A304676.
EXAMPLE
Some solutions for n=5
..0..1..1..1..0. .0..1..1..0..1. .0..1..1..1..1. .0..0..1..1..0
..1..0..1..0..1. .0..1..0..0..0. .1..0..0..0..0. .0..0..1..0..1
..0..1..0..1..0. .0..0..1..1..1. .1..0..1..1..0. .1..1..1..1..0
..0..1..0..1..0. .0..1..0..0..1. .1..0..1..0..1. .1..1..1..1..0
..1..0..1..1..0. .1..0..1..1..0. .1..0..0..1..0. .1..1..1..1..0
CROSSREFS
Cf. A304676.
Sequence in context: A159595 A009300 A192372 * A316117 A149477 A149478
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 16 2018
STATUS
approved