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A265439
Number of n X n 0..2n-2 arrays with upper left zero and lower right 2n-2 and each element differing from its horizontal and vertical neighbors by one or two.
0
1, 1, 145, 57721, 41855199, 569620472894, 7361174970568815, 1484662166072017164173, 589336120060277543986621142
OFFSET
1,3
COMMENTS
Diagonal of A265447.
EXAMPLE
Some solutions for n=4
..0..2..4..2....0..2..1..2....0..2..0..1....0..2..3..4....0..2..4..5
..2..0..2..4....2..1..3..4....2..3..1..2....1..3..1..3....2..3..5..6
..1..2..4..5....3..2..4..5....0..1..2..4....3..1..2..4....4..5..6..4
..3..4..5..6....5..4..5..6....1..3..4..6....1..2..4..6....2..3..4..6
CROSSREFS
Cf. A265447.
Sequence in context: A097730 A283520 A359013 * A060720 A015081 A015055
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 09 2015
STATUS
approved