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A186560
Number of (n+2)X3 0..2 arrays with every 3X3 subblock commuting with each horizontal and vertical neighbor 3X3 subblock
1
19683, 721, 2917, 6594, 12122, 20056, 29303, 35198, 53611, 85029, 121783, 199305, 321297, 465750, 728568, 1143162, 1676187, 2600987, 4073323, 6071427, 9378717, 14610267, 21959403, 33776511, 52386811, 79228491, 121620695, 188062383
OFFSET
1,1
COMMENTS
Column 1 of A186568
LINKS
FORMULA
Empirical: a(n)=2*a(n-1)-a(n-2)+2*a(n-3)-4*a(n-4)+2*a(n-5)+2*a(n-6)-2*a(n-7) for n>18
EXAMPLE
Some solutions for 4X3
..1..2..2....0..0..0....0..1..0....0..0..0....0..0..0....1..1..0....1..2..0
..2..2..0....0..0..0....0..0..1....0..0..0....0..0..0....0..0..0....0..2..0
..0..2..2....2..2..0....2..0..0....2..1..0....0..0..0....0..0..0....0..1..0
..2..1..0....0..2..2....0..2..0....2..1..1....2..0..2....0..1..2....0..0..1
CROSSREFS
Sequence in context: A321825 A186559 A186568 * A046322 A224658 A224654
KEYWORD
nonn
AUTHOR
R. H. Hardin Feb 23 2011
STATUS
approved