A206065 Number of (n+1) X 2 0..2 arrays with every 2 X 3 or 3 X 2 subblock having exactly three clockwise edge increases.

81, 150, 537, 2052, 7878, 29760, 112236, 423288, 1596672, 6022920, 22719480, 85701576, 323280168, 1219464936, 4600018536, 17352012360, 65454591240, 246905282472, 931366575720, 3513265045128, 13252602787272, 49990956668904

Offset

1,1

Comments

Column 1 of A206072.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) - a(n-2) + 2*a(n-4) for n>5.

Empirical g.f.: 3*x*(27 - 58*x + 6*x^2 + 18*x^3 + 15*x^4) / (1 - 4*x + x^2 - 2*x^4). - Colin Barker, Jun 13 2018

Example

Some solutions for n=4:
..0..1....2..0....1..2....2..1....2..0....0..2....1..2....2..1....2..2....1..1
..2..2....0..0....0..0....2..2....1..2....2..2....0..1....0..2....0..0....2..2
..1..1....2..1....1..1....1..0....0..1....1..0....2..2....1..0....2..1....1..0
..0..2....0..2....0..2....2..1....0..2....0..2....0..0....2..1....0..2....0..1
..2..1....1..0....2..1....0..2....2..1....2..0....2..1....1..0....1..0....1..0

Crossrefs

Cf. A206072.

Sequence in context: A207050 A206072 A207043 * A139705 A226643 A353456

Adjacent sequences: A206062 A206063 A206064 * A206066 A206067 A206068

Keyword

nonn

Author

R. H. Hardin, Feb 03 2012

Status

approved