A265459 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 antidiagonal neighbors by one or two.

1, 3, 550, 398508, 2002867877, 49094408347776, 6109458550119472926, 3756191694523776480082260, 11421616015549105186265908485988

Offset

1,2

Comments

Diagonal of A265466.

Links

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

Example

Some solutions for n=3
..0..2..4....0..2..1....0..2..3....0..2..3....0..1..2....0..2..0....0..2..3
..3..2..1....3..2..0....3..2..1....0..2..4....2..3..4....0..2..0....3..2..0
..1..3..4....1..2..4....1..3..4....3..2..4....2..3..4....0..2..4....4..2..4

Crossrefs

Cf. A265466.

Sequence in context: A332153 A158247 A034314 * A201431 A171359 A002306

Adjacent sequences: A265456 A265457 A265458 * A265460 A265461 A265462

Keyword

nonn

Author

R. H. Hardin, Dec 09 2015

Status

approved