A200794 Number of n X n 0..3 arrays with values 0..3 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors.

1, 15, 9880, 132636590, 26207146328784, 75743730886453371522, 3202145671418507455058837791

Offset: 1

Author

R. H. Hardin Nov 22 2011

Keywords

• nonn

Comments

Diagonal of A200801

Examples

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