A193610 Number of n X n symmetric 0..3 arrays with no element equal to the sum mod 4 of all its horizontal and vertical neighbors.

3, 27, 729, 59240, 14349636, 10460353203, 22876792454961, 150094635296999121, 2954312847295467367104

Offset

1,1

Links

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

Example

Some solutions for 4 X 4
..0..1..3..3....1..1..2..2....0..3..3..2....0..3..2..0....1..0..2..3
..1..3..1..2....1..1..1..1....3..1..1..2....3..0..2..0....0..0..1..3
..3..1..3..3....2..1..2..1....3..1..1..1....2..2..2..0....2..1..1..1
..3..2..3..3....2..1..1..3....2..2..1..3....0..0..0..3....3..3..1..3

Crossrefs

Sequence in context: A113100 A038379 A047656 * A052269 A138525 A185149

Adjacent sequences: A193607 A193608 A193609 * A193611 A193612 A193613

Keyword

nonn

Author

R. H. Hardin, Jul 31 2011

Status

approved