A233019 Number of n X n 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally, vertically, diagonally or antidiagonally, and top left element zero

1, 15, 849, 179999, 149128385, 487651369463, 6338787392715565, 328918675019714663095, 68332288847776936953486283, 56955693489584720827393016043135

Offset

1,2

Comments

Diagonal of A233026

Links

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

Example

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

Crossrefs

Sequence in context: A020240 A281695 A223276 * A270962 A223818 A208349

Adjacent sequences: A233016 A233017 A233018 * A233020 A233021 A233022

Keyword

nonn

Author

R. H. Hardin, Dec 03 2013

Status

approved