A206015 Number of (n+1) X 3 0..3 arrays with the number of clockwise edge increases in every 2 X 2 subblock unequal to the number of counterclockwise edge increases.

680, 7688, 87448, 996840, 11364568, 129573608, 1477339224, 16844007528, 192048333016, 2189655169000, 24965536560472, 284646655571816, 3245422674678232, 37002958353850088, 421892327778797144

Offset

1,1

Comments

Column 2 of A206021.

Links

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

Formula

Empirical: a(n) = 14*a(n-1) - 23*a(n-2) - 94*a(n-3) + 216*a(n-4) - 64*a(n-5).

Empirical g.f.: 8*x*(85 - 229*x - 568*x^2 + 1664*x^3 - 512*x^4) / ((1 - 2*x)*(1 - 12*x - x^2 + 92*x^3 - 32*x^4)). - Colin Barker, Jun 13 2018

Example

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

Crossrefs

Cf. A206021.

Sequence in context: A235013 A154036 A185765 * A202908 A309245 A118509

Adjacent sequences: A206012 A206013 A206014 * A206016 A206017 A206018

Keyword

nonn

Author

R. H. Hardin, Feb 02 2012

Status

approved