A205635 Number of (n+1)X2 0..3 arrays with every 2 X 2 subblock having the number of clockwise edge increases equal to the number of counterclockwise edge increases in its adjacent leftward and upward neighbors.

256, 2320, 21416, 198688, 1843744, 17111320, 158804736, 1473828208, 13678225256, 126944238720, 1178138077344, 10934009198136, 101475844940512, 941772325426928, 8740357030533704, 81117101420015392, 752827845002975520

Offset

1,1

Comments

Column 1 of A205642.

Links

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

Formula

Empirical: a(n) = 16*a(n-1) -64*a(n-2) -46*a(n-3) +680*a(n-4) -1040*a(n-5) -73*a(n-6) +912*a(n-7) -228*a(n-8) -176*a(n-9) +20*a(n-10).

Example

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

Crossrefs

Sequence in context: A206102 A014713 A205642 * A205027 A207300 A205020

Adjacent sequences: A205632 A205633 A205634 * A205636 A205637 A205638

Keyword

nonn

Author

R. H. Hardin, Jan 29 2012

Status

approved