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A296398
Number of n X n 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 2 or 3 neighboring 1's.
0
1, 4, 24, 444, 35561, 6200926, 3068113721, 4427644444522, 16720185055951726, 174611744359086830290, 5039863866276836681199376
OFFSET
1,2
COMMENTS
Diagonal of A296405.
EXAMPLE
Some solutions for n=5
..0..1..1..1..1. .0..1..1..1..0. .1..1..1..0..0. .0..1..1..1..0
..1..1..0..1..0. .0..1..0..1..0. .1..0..1..1..1. .0..1..0..1..1
..0..0..0..1..1. .1..0..0..1..1. .1..0..0..1..1. .1..0..1..0..1
..1..1..1..0..1. .1..1..0..0..1. .1..0..0..0..1. .1..1..1..1..1
..1..0..1..1..0. .1..0..0..1..1. .1..1..1..1..1. .0..0..0..0..0
CROSSREFS
Cf. A296405.
Sequence in context: A247737 A326871 A012945 * A166947 A103624 A101952
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 11 2017
STATUS
approved