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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. 1
1764, 3888, 14715, 39450, 191766, 526680, 2500875, 6985128, 33846264, 94355988, 454693140, 1269412704, 6131489892, 17111113680, 82584274404, 230506000944, 1112836444476, 3105929013420, 14993191433262, 41846929098264 (list; graph; refs; listen; history; text; internal format)
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

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Last modified July 19 09:33 EDT 2019. Contains 325155 sequences. (Running on oeis4.)