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.

256, 1888, 15680, 139744, 1289472, 12105120, 114566336, 1088409696, 10358308480, 98658758944, 940033716800, 8958289929184, 85376964317184, 813714139891872, 7755506295392192, 73918257610362720, 704522374079236480

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