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A205910
Number of (n+1) X (n+1) 0..2 arrays with every 2 X 2 subblock having the same number of clockwise edge increases as its horizontal neighbors and the same number of counterclockwise edge increases as its vertical neighbors.
0
81, 1791, 87918, 14150391, 6011669886, 6566654061039, 18225426305218983, 128865421969802643036, 2315569396435124102371935
OFFSET
1,1
COMMENTS
Diagonal of A205917.
EXAMPLE
Some solutions for n=4:
..1..0..2..2..0....1..0..0..1..2....2..2..2..0..1....2..1..0..1..0
..0..0..0..0..0....0..2..1..0..2....0..2..0..0..0....2..1..1..1..1
..0..1..1..1..0....0..1..1..2..2....2..2..0..2..2....1..1..2..1..2
..0..0..1..0..0....1..0..2..1..0....0..2..2..2..0....0..1..1..1..1
..0..1..1..0..2....1..2..2..0..0....2..2..0..0..0....0..1..0..0..1
CROSSREFS
Sequence in context: A237801 A328683 A236057 * A236811 A206669 A223206
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 01 2012
STATUS
approved