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A296535
Number of n X n 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 2 or 4 neighboring 1's.
0
1, 3, 16, 126, 2104, 78660, 5705431, 820373528, 239372827502, 141301759543525, 168080053760638246, 403684916425998696873
OFFSET
1,2
COMMENTS
Diagonal of A296541.
EXAMPLE
Some solutions for n=6
..0..1..0..0..0..0. .0..0..0..1..0..0. .0..0..0..1..1..0. .0..1..1..1..1..0
..1..1..0..1..1..0. .0..1..1..1..0..0. .0..0..1..0..1..0. .1..0..0..0..1..0
..0..0..1..0..1..0. .0..1..0..0..0..0. .0..1..0..0..1..0. .1..1..1..1..0..0
..0..1..0..0..1..0. .1..1..0..1..0..0. .0..1..0..0..1..1. .0..0..0..0..0..0
..1..0..1..1..0..0. .0..0..1..1..0..0. .1..0..0..0..0..1. .0..0..0..0..0..0
..1..1..0..0..0..0. .0..0..0..0..0..0. .1..1..1..1..1..0. .0..0..0..0..0..0
CROSSREFS
Cf. A296541.
Sequence in context: A247591 A188805 A214645 * A088358 A082161 A264636
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 15 2017
STATUS
approved