A186879 Number of (n+2)X9 0..3 arrays with every 3X3 subblock commuting with each horizontal and vertical neighbor 3X3 subblock

277659, 21661, 37576, 121144, 260584, 338176, 443560, 571984, 798832, 1272712, 2086288, 3350152, 5585728, 9225664, 15403771, 25918654, 43087345, 71662141, 119953993, 199127077, 331052797, 553674334, 920445640, 1531199242, 2558915851

Offset

1,1

Comments

Column 7 of A186881

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=2*a(n-1)-a(n-2)+3*a(n-3)-6*a(n-4)+3*a(n-5)+3*a(n-6)-3*a(n-7) for n>15

Example

Some solutions for 4X9
..1..0..0..0..0..0..0..2..3....0..0..0..0..0..0..0..1..3
..0..0..0..0..0..0..0..0..0....3..0..0..0..0..0..0..0..1
..0..0..0..0..0..0..0..0..0....0..3..0..0..0..0..0..0..0
..0..1..0..0..0..0..0..0..0....2..0..3..0..0..0..0..0..0

Crossrefs

Sequence in context: A271349 A295472 A162765 * A224252 A236017 A252209

Adjacent sequences: A186876 A186877 A186878 * A186880 A186881 A186882

Keyword

nonn

Author

R. H. Hardin Feb 28 2011

Status

approved