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%I #7 Dec 11 2015 11:45:22
%S 81,60,162,486,1458,4374,13122,39366,118098,354294,1062882,3188646,
%T 9565938,28697814,86093442,258280326,774840978,2324522934,6973568802,
%U 20920706406,62762119218,188286357654,564859072962,1694577218886
%N Number of (n+1) X 2 0..2 arrays with every 2 X 3 or 3 X 2 subblock having exactly three counterclockwise and three clockwise edge increases.
%C Column 1 of A206150.
%H R. H. Hardin, <a href="/A206143/b206143.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) for n > 3.
%e Some solutions for n=4:
%e ..1..2....0..2....2..1....2..1....2..0....1..2....2..1....1..2....0..2....1..2
%e ..0..1....1..0....0..2....0..2....0..1....2..0....0..2....2..1....1..0....2..0
%e ..1..0....2..1....2..0....1..0....2..0....0..1....1..0....0..2....2..1....1..2
%e ..0..2....0..2....1..2....2..1....0..2....2..0....2..1....1..0....1..0....0..1
%e ..2..0....2..1....2..0....1..2....1..0....1..2....1..0....2..1....0..1....1..2
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 04 2012
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