A205731 Number of (n+1)X4 0..2 arrays with every 2 X 2 subblock having the same number of clockwise edge increases as its horizontal neighbors and no 2 X 2 subblock having the same number of counterclockwise edge increases as its vertical neighbors.

1764, 3888, 14715, 39450, 191766, 526680, 2500875, 6985128, 33846264, 94355988, 454693140, 1269412704, 6131489892, 17111113680, 82584274404, 230506000944, 1112836444476, 3105929013420, 14993191433262, 41846929098264

Offset

1,1

Comments

Column 3 of A205736.

Links

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

Formula

Empirical: a(n) = 15*a(n-2) -5*a(n-4) -268*a(n-6) +871*a(n-8) -1225*a(n-10) +919*a(n-12) -364*a(n-14) +60*a(n-16) for n>21.

Example

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

Crossrefs

Sequence in context: A213804 A252309 A141039 * A151769 A165678 A205912

Adjacent sequences: A205728 A205729 A205730 * A205732 A205733 A205734

Keyword

nonn

Author

R. H. Hardin, Jan 30 2012

Status

approved