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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A186568

LINKS

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

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

Adjacent sequences:  A186557 A186558 A186559 * A186561 A186562 A186563

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 23 2011

STATUS

approved

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Last modified December 7 13:06 EST 2021. Contains 349581 sequences. (Running on oeis4.)