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

1,1

Comments

Diagonal of A209517.

Links

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

Example

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

Crossrefs

Sequence in context: A218240 A281567 A012165 * A132783 A221445 A218353

Adjacent sequences: A209509 A209510 A209511 * A209513 A209514 A209515

Keyword

nonn

Author

R. H. Hardin, Mar 09 2012

Status

approved