A205937 Number of (n+1) X 2 0..3 arrays with no 2 X 2 subblock having the number of clockwise edge increases equal to the number of counterclockwise edge increases in its adjacent leftward or upward neighbors.

256, 1776, 12712, 91440, 656272, 4711264, 33827496, 242859696, 1743558448, 12517828752, 89871316488, 645223555056, 4632334222640, 33257550378496, 238770342344520, 1714234994048944, 12307232871040912, 88358941969931504

Offset

1,1

Comments

Column 1 of A205944.

Links

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

Formula

Empirical: a(n) = 16*a(n-2) + 132*a(n-3) + 626*a(n-4) + 1504*a(n-5) + 2204*a(n-6) + 2140*a(n-7) + 1011*a(n-8) + 96*a(n-9) + 80*a(n-10).

Example

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

Crossrefs

Sequence in context: A238311 A205944 A238306 * A237911 A237905 A238145

Adjacent sequences: A205934 A205935 A205936 * A205938 A205939 A205940

Keyword

nonn

Author

R. H. Hardin, Feb 01 2012

Status

approved