A209512 Number of (n+1) X (n+1) 0..2 arrays with the number of clockwise edge increases in every 2 X 2 subblock equal to the number of counterclockwise edge increases.

57, 4995, 2071311, 4099186545, 38883961392081, 1772313933013227273, 388756746462464273412765, 410796134340987241848792211659, 2092643007412378548345728130194640495

Offset: 1

Author

R. H. Hardin, Mar 09 2012

Keywords

• nonn

Comments

Diagonal of A209517.

Examples

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

Links

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