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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.

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`%I #7 Oct 09 2015 22:37:27
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`%S 1764,3888,14715,39450,191766,526680,2500875,6985128,33846264,
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`%T 94355988,454693140,1269412704,6131489892,17111113680,82584274404,
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`%U 230506000944,1112836444476,3105929013420,14993191433262,41846929098264
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`%N 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.
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`%C Column 3 of A205736.
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`%H R. H. Hardin, <a href="/A205731/b205731.txt">Table of n, a(n) for n = 1..210</a>
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`%F 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.
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`%e Some solutions for n=4:
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`%e ..1..2..0..2....1..2..2..0....2..0..0..0....1..0..1..2....2..1..1..1
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`%e ..2..2..2..2....2..1..0..2....2..2..2..2....0..2..0..2....2..2..2..2
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`%e ..2..2..2..2....2..2..2..2....2..2..2..2....0..2..0..1....2..2..2..2
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`%e ..1..2..1..2....2..2..2..2....1..2..0..1....1..0..2..2....2..0..1..2
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`%e ..0..1..2..1....1..1..2..1....2..1..2..1....1..0..0..1....1..2..2..1
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`%K nonn
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`%O 1,1
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`%A _R. H. Hardin_, Jan 30 2012
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