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A300420
Number of n X n 0..1 arrays with every element equal to 1, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
0
0, 3, 53, 2227, 240196, 67378450, 48707694395, 90693182026546, 435112536711313866, 5381527099060030118335, 171582103150798864303410622
OFFSET
1,2
COMMENTS
Diagonal of A300427.
EXAMPLE
Some solutions for n=5
..0..0..0..0..1. .0..0..0..0..0. .0..0..0..1..1. .0..0..0..1..1
..0..1..0..1..1. .1..0..1..0..0. .0..1..0..1..0. .1..1..0..0..0
..0..1..0..1..0. .1..0..1..1..0. .0..1..0..1..0. .0..1..1..0..1
..0..1..0..0..0. .0..0..1..0..0. .1..1..0..0..1. .0..0..1..0..1
..1..1..1..1..0. .1..1..0..1..1. .0..0..1..1..1. .0..0..1..1..1
CROSSREFS
Cf. A300427.
Sequence in context: A012823 A098932 A100444 * A300683 A296678 A227051
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 05 2018
STATUS
approved