A208487 Number of (n+1) X 4 0..3 arrays with the number of clockwise edge increases in every 2 X 2 subblock equal to the number of counterclockwise edge increases.

13800, 773288, 43689232, 2473041560, 140051200968, 7932164084608, 449271828443912, 25446613122575176, 1441290961315589072, 81634469371271854648, 4623762824135968860328, 261889170973575575061248

Offset

1,1

Comments

Column 3 of A208492.

Links

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

Formula

Empirical: a(n) = 107*a(n-1) - 3877*a(n-2) + 69003*a(n-3) - 688480*a(n-4) + 4042126*a(n-5) - 13877475*a(n-6) + 25524339*a(n-7) - 15376881*a(n-8) - 25497923*a(n-9) + 51893722*a(n-10) - 31287236*a(n-11) + 2987776*a(n-12) + 2213392*a(n-13).

Example

Some solutions for n=4:
..3..2..3..0....2..1..1..0....0..3..3..3....0..0..2..1....2..0..3..0
..1..3..1..2....3..2..1..1....2..1..1..1....1..0..2..1....2..0..3..3
..2..1..2..3....0..3..2..2....0..2..1..0....0..1..0..2....1..2..0..3
..0..2..2..2....3..1..3..2....3..0..2..1....2..3..1..3....0..1..2..0
..0..2..3..2....0..2..0..3....3..3..0..3....1..2..3..0....2..3..1..2

Crossrefs

Sequence in context: A031807 A119730 A204839 * A188102 A109102 A250822

Adjacent sequences: A208484 A208485 A208486 * A208488 A208489 A208490

Keyword

nonn

Author

R. H. Hardin, Feb 27 2012

Status

approved