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A209907 Half the number of (n+1)X3 0..3 arrays with every 2X2 subblock having two or four distinct clockwise edge differences 1
562, 13098, 295448, 6711168, 152153160, 3452051294, 78298719958, 1776153151954, 40289004709802, 913904480044196, 20730591242525088, 470244787257936734, 10666837893533545782, 241962270764619764754, 5488573721848784927246 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A209913

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 16*a(n-1) +227*a(n-2) -1440*a(n-3) -8244*a(n-4) +46409*a(n-5) +53926*a(n-6) -406100*a(n-7) -117231*a(n-8) +1484559*a(n-9) +166049*a(n-10) -2587430*a(n-11) -386782*a(n-12) +2096907*a(n-13) +472125*a(n-14) -660956*a(n-15) -166954*a(n-16) +44616*a(n-17) +4488*a(n-18) -192*a(n-19)

EXAMPLE

Some solutions for n=4

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

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

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

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

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

CROSSREFS

Sequence in context: A121508 A252344 A250976 * A232679 A135437 A142759

Adjacent sequences:  A209904 A209905 A209906 * A209908 A209909 A209910

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 15 2012

STATUS

approved

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Last modified September 23 11:23 EDT 2020. Contains 337310 sequences. (Running on oeis4.)