

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
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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(n2) 5*a(n4) 268*a(n6) +871*a(n8) 1225*a(n10) +919*a(n12) 364*a(n14) +60*a(n16) 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



