A193500 Number of n X n symmetric 0..3 arrays with no element equal to the product mod 4 of any two of its horizontal and vertical neighbors

4, 30, 476, 16922, 1328430, 224738251, 82830799570, 66307508721755, 115414300257319497, 435721788093736397288, 3576788708181112341917385, 63678865525598948282213562255, 2464034493065067438484568541197974

Offset

1,1

Links

Table of n, a(n) for n=1..13.

Example

Some solutions for 4X4
..3..0..1..1....2..0..1..3....0..3..3..3....3..0..3..2....3..3..3..2
..0..2..3..2....0..3..1..0....3..0..3..3....0..3..0..1....3..3..3..0
..1..3..2..1....1..1..0..3....3..3..3..0....3..0..3..2....3..3..2..3
..1..2..1..2....3..0..3..2....3..3..0..1....2..1..2..3....2..0..3..2

Crossrefs

Sequence in context: A351795 A290058 A168129 * A163885 A120338 A064050

Adjacent sequences: A193497 A193498 A193499 * A193501 A193502 A193503

Keyword

nonn

Author

R. H. Hardin Jul 29 2011

Status

approved