A206686 Number of n X n 0..3 arrays with no element equal to another within two positions in the same row or column, and new values 0..3 introduced in row major order.

1, 4, 44, 916, 31504, 1915580, 208563912, 41832855136, 15644344542416, 10971573350181154

Offset: 1

Author

R. H. Hardin Feb 11 2012

Keywords

• nonn

Comments

Diagonal of A206692

Examples

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