A206014 Number of (n+1) X 2 0..3 arrays with the number of clockwise edge increases in every 2 X 2 subblock unequal to the number of counterclockwise edge increases.

104, 680, 4440, 29000, 189400, 1237000, 8079000, 52765000, 344615000, 2250725000, 14699775000, 96006125000, 627028375000, 4095203125000, 26746299375000, 174683528125000, 1140880634375000, 7451238453125000, 48664998609375000

Offset

1,1

Comments

Column 1 of A206021.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) + 10*a(n-2).

Empirical g.f.: 8*x*(13 + 20*x) / (1 - 5*x - 10*x^2). - Colin Barker, Jun 13 2018

Example

Some solutions for n=3:
..3..0....0..2....1..0....1..0....1..1....3..0....1..3....1..0....0..1....2..0
..1..0....1..1....3..3....1..2....2..3....1..0....0..3....2..3....0..2....1..0
..3..3....3..2....2..0....3..2....0..3....1..2....0..1....2..1....1..1....1..3
..0..1....0..0....2..3....3..0....1..1....3..2....3..3....2..3....0..2....0..0

Crossrefs

Cf. A206021.

Sequence in context: A250676 A250677 A206021 * A106298 A337145 A230028

Adjacent sequences: A206011 A206012 A206013 * A206015 A206016 A206017

Keyword

nonn

Author

R. H. Hardin, Feb 02 2012

Status

approved