A186473 Number of (n+1)X(n+1) 0..3 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors

256, 362, 4686, 16762, 107353, 305089, 1849873, 5977657, 34498177, 116855689, 634602529, 2242113937, 11691520969, 42863613697, 216155958361, 816595120705, 4006518195025, 15513728255737, 74427875789953, 294085455103369

Offset

1,1

Comments

Diagonal of A186482

Links

R. H. Hardin, Table of n, a(n) for n = 1..29

Example

Some solutions for 3X3
..2..0..3....1..0..1....1..2..1....3..2..0....2..0..0....0..0..0....2..0..0
..0..2..0....0..1..0....2..1..2....0..0..2....0..2..0....0..0..0....0..0..0
..0..0..2....0..0..1....1..2..1....0..0..3....3..0..2....1..1..1....0..0..1

Crossrefs

Sequence in context: A352595 A345534 A345786 * A046309 A036332 A114987

Adjacent sequences: A186470 A186471 A186472 * A186474 A186475 A186476

Keyword

nonn

Author

R. H. Hardin Feb 22 2011

Status

approved