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A206679 Number of (n+1) X 3 0..2 arrays with every 2 X 3 or 3 X 2 subblock having an unequal number of clockwise and counterclockwise edge increases. 1
306, 1728, 9792, 55836, 317736, 1809324, 10300608, 58646916, 333899064, 1901032092, 10823363424, 61621963812, 350839639224, 1997477224380, 11372475138624, 64748269110564, 368639041055544, 2098816612656732 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A206685.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) + 13*a(n-2) + 11*a(n-3) + 12*a(n-4) + 6*a(n-5) for n>6.

Empirical g.f.: 18*x*(17 + 45*x + 35*x^2 + 35*x^3 + 14*x^4 - 2*x^5) / (1 - 3*x - 13*x^2 - 11*x^3 - 12*x^4 - 6*x^5). - Colin Barker, Jun 17 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Cf. A206685.

Sequence in context: A236012 A158589 A030030 * A172966 A223073 A064257

Adjacent sequences:  A206676 A206677 A206678 * A206680 A206681 A206682

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 11 2012

STATUS

approved

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Last modified August 5 06:46 EDT 2020. Contains 336209 sequences. (Running on oeis4.)