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.

1, 1, 145, 57721, 41855199, 569620472894, 7361174970568815, 1484662166072017164173, 589336120060277543986621142

Offset

1,3

Comments

Diagonal of A265447.

Links

Table of n, a(n) for n=1..9.

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

Adjacent sequences: A265436 A265437 A265438 * A265440 A265441 A265442

Keyword

nonn

Author

R. H. Hardin, Dec 09 2015

Status

approved