A230657 Number of n X n 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2-x(i,j)

1, 3, 15, 123, 8613, 337977, 169006665, 40860127671, 131515599970167, 201844710508818147, 4141132208926170478473, 40464088148356899296269059

Offset

1,2

Comments

Diagonal of A230661

Links

Table of n, a(n) for n=1..12.

Example

Some solutions for n=5
..x..1..x..1..x....x..2..x..0..x....x..1..x..1..x....x..1..x..1..x
..1..x..1..x..1....0..x..1..x..2....1..x..0..x..1....1..x..2..x..1
..x..2..x..2..x....x..1..x..0..x....x..2..x..1..x....x..0..x..0..x
..0..x..1..x..0....2..x..2..x..1....2..x..1..x..2....2..x..0..x..2
..x..2..x..1..x....x..0..x..1..x....x..0..x..0..x....x..2..x..0..x

Crossrefs

Sequence in context: A191371 A113077 A251661 * A246573 A270503 A212553

Adjacent sequences: A230654 A230655 A230656 * A230658 A230659 A230660

Keyword

nonn

Author

R. H. Hardin, Oct 27 2013

Status

approved