A206651 Number of (n+2)X(n+2) 0..1 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly two ways, and new values 0..1 introduced in row major order

102, 1769, 50529, 2324028, 175401820, 21966491761, 4505251075150, 1530992805584457

Offset

1,1

Comments

Diagonal of A206659

Links

Table of n, a(n) for n=1..8.

Example

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

Crossrefs

Sequence in context: A200452 A204859 A205425 * A163435 A223308 A230737

Adjacent sequences: A206648 A206649 A206650 * A206652 A206653 A206654

Keyword

nonn

Author

R. H. Hardin Feb 11 2012

Status

approved