A206269 Number of (n+1) X (n+1) 0..2 arrays with no 2 X 2 subblock having the number of clockwise edge increases equal to the number of counterclockwise edge increases in its adjacent leftward or upward neighbors.

81, 972, 12429, 145824, 2243139, 39044748, 964315869, 27362301828, 1106854279383, 53489846569626, 3690406822607805

Offset

1,1

Comments

Diagonal of A206277.

Links

Table of n, a(n) for n=1..11.

Example

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

Crossrefs

Sequence in context: A173810 A205047 A086580 * A236885 A205729 A237226

Adjacent sequences: A206266 A206267 A206268 * A206270 A206271 A206272

Keyword

nonn

Author

R. H. Hardin, Feb 05 2012

Status

approved