A208169 Number of n X n 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors.

1, 13, 8469, 99752346, 16567902881244, 38625516979536823947, 1263976383376771173195964686, 580579239138791881884932674640711196, 3743190521310525744113304412007474906812935048

Offset: 1

Author

R. H. Hardin Feb 24 2012

Keywords

• nonn

Comments

Diagonal of A208175

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..10