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A186481 Number of (n+1)X9 0..3 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors 1
27101, 35081, 101108, 286290, 479785, 1286113, 1894849, 5977657, 8078233, 25049545, 34600393, 103930809, 154520201, 437740901, 693356465, 1854858401, 3085313121, 7883094433, 13654582357, 33612555865, 60183013369, 143706271561 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 8 of A186482

LINKS

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

FORMULA

Empirical: a(n)=2*a(n-1)+2*a(n-2)-6*a(n-3)+6*a(n-4)-3*a(n-5) for n>19

EXAMPLE

Some solutions for 3X9

..1..0..3..0..1..0..1..0..1....2..2..0..2..0..1..0..0..0

..0..1..0..3..0..1..0..1..0....2..0..2..0..2..0..1..0..0

..2..0..1..0..3..0..1..0..1....0..2..0..2..0..2..0..1..1

CROSSREFS

Sequence in context: A236825 A164522 A037045 * A210073 A236275 A228562

Adjacent sequences:  A186478 A186479 A186480 * A186482 A186483 A186484

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 22 2011

STATUS

approved

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Last modified September 17 08:31 EDT 2019. Contains 327127 sequences. (Running on oeis4.)