A187432 Number of (n+1) X (n+1) 0..2 arrays with no 2 X 2 subblock commuting with any of its horizontal and vertical 2 X 2 subblock neighbors.

81, 14178, 18257013, 167339492229, 10892264636400698

Offset

1,1

Comments

Diagonal of A187441.

Links

Table of n, a(n) for n=1..5.

Example

Some solutions for 3 X 3
..1..1..0....1..1..2....1..1..0....2..0..2....1..0..0....1..0..1....2..1..0
..1..2..0....2..1..0....1..2..2....1..1..1....2..1..2....1..1..0....1..1..0
..2..0..1....1..1..1....1..1..1....1..0..1....2..2..2....0..2..2....1..2..2

Crossrefs

Cf. A187441.

Sequence in context: A053905 A184690 A143005 * A017104 A243007 A143653

Adjacent sequences: A187429 A187430 A187431 * A187433 A187434 A187435

Keyword

nonn

Author

R. H. Hardin, Mar 10 2011

Status

approved