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A317758
Number of nXn 0..1 arrays with every element unequal to 0, 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
0
1, 6, 16, 43, 109, 266, 639, 1529, 3674, 8909, 21853, 54252, 136213, 345373, 882828, 2271143, 5871373, 15234214, 39633091, 103306417, 269641062, 704462713, 1841692605, 4816973880, 12602801545
OFFSET
1,2
COMMENTS
Diagonal of A317764.
EXAMPLE
Some solutions for n=5
..0..1..1..1..1. .0..1..1..1..1. .0..1..1..1..1. .0..0..0..0..0
..1..1..1..1..1. .1..1..1..1..1. .1..1..1..1..1. .0..0..0..0..0
..0..0..0..0..0. .1..1..1..1..1. .1..1..1..1..1. .0..0..0..0..0
..0..0..0..0..1. .1..1..1..1..1. .1..1..1..1..0. .0..0..0..0..0
..0..0..0..1..1. .0..0..0..0..0. .1..1..1..0..0. .0..0..0..0..1
CROSSREFS
Cf. A317764.
Sequence in context: A283330 A263325 A107614 * A010915 A352115 A260384
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 06 2018
STATUS
approved