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A206745 Number of (n+1) X 2 0..3 arrays with every 2 X 3 or 3 X 2 subblock having an equal number of clockwise and counterclockwise edge increases. 1
256, 1888, 15680, 139744, 1289472, 12105120, 114566336, 1088409696, 10358308480, 98658758944, 940033716800, 8958289929184, 85376964317184, 813714139891872, 7755506295392192, 73918257610362720, 704522374079236480 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A206752.

LINKS

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

FORMULA

Empirical: a(n) = 15*a(n-1) - 55*a(n-2) + 17*a(n-3) + 108*a(n-4) - 84*a(n-5).

Empirical g.f.: 32*x*(8 - 61*x + 45*x^2 + 126*x^3 - 126*x^4) / ((1 - x)*(1 - 3*x - 6*x^2)*(1 - 11*x + 14*x^2)). - Colin Barker, Jun 17 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Cf. A206752.

Sequence in context: A237544 A206752 A237539 * A237791 A237786 A238063

Adjacent sequences:  A206742 A206743 A206744 * A206746 A206747 A206748

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 12 2012

STATUS

approved

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Last modified October 7 13:15 EDT 2022. Contains 357271 sequences. (Running on oeis4.)