A265451 Number of n X 1 0..n+1-2 arrays with each element differing from its horizontal and vertical neighbors by one or two.

1, 1, 2, 12, 66, 360, 1864, 9358, 45642, 217590, 1017626, 4684896, 21284488, 95624666, 425523864, 1878025074, 8229470812, 35836393568, 155196577484, 668832795812, 2869861291134, 12266161148622, 52243167132940, 221803857150698, 938974990229088, 3964558585350392

Offset

0,3

Links

Alois P. Heinz, Table of n, a(n) for n = 0..500 (terms n = 1..210 from R. H. Hardin)

Example

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

Crossrefs

Column 1 of A265458.

Cf. A102699.

Sequence in context: A197745 A323925 A039633 * A180195 A212389 A241074

Adjacent sequences: A265448 A265449 A265450 * A265452 A265453 A265454

Keyword

nonn

Author

R. H. Hardin, Dec 09 2015

Extensions

a(0)=1 prepended by Alois P. Heinz, Oct 25 2022

Status

approved