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A205818 Number of (n+1) X 4 0..2 arrays with the number of clockwise edge increases in every 2 X 2 subblock unequal to the number of counterclockwise edge increases.

%I A205818 #10 Jun 12 2018 11:12:55
%S A205818 180,714,2880,12318,53100,230532,1002240,4361064,18980472,82617132,
%T A205818 359622708,1565418528,6814215036,29662110636,129118523304,
%U A205818 562050276348,2446593518052,10649972628456,46359118343628,201800318106108
%N A205818 Number of (n+1) X 4 0..2 arrays with the number of clockwise edge increases in every 2 X 2 subblock unequal to the number of counterclockwise edge increases.
%C A205818 Column 3 of A205823.
%H A205818 R. H. Hardin, <a href="/A205818/b205818.txt">Table of n, a(n) for n = 1..210</a>
%F A205818 Empirical: a(n) = 3*a(n-1) + 10*a(n-2) - 13*a(n-3) - 25*a(n-4) + 12*a(n-5) + 18*a(n-6) - 2*a(n-8).
%F A205818 Empirical g.f.: 6*x*(30 + 29*x - 177*x^2 - 187*x^3 + 188*x^4 + 197*x^5 - 5*x^6 - 23*x^7) / ((1 - x - x^2)*(1 - 2*x - 11*x^2 + 14*x^4 + 2*x^5 - 2*x^6)). - _Colin Barker_, Jun 12 2018
%e A205818 Some solutions for n=4:
%e A205818 ..1..0..0..2....0..0..2..2....2..2..2..0....1..1..1..0....1..2..1..1
%e A205818 ..1..2..1..2....2..1..1..0....1..0..1..0....2..0..2..2....1..0..0..2
%e A205818 ..1..0..1..0....2..0..2..2....1..2..1..2....2..1..1..0....2..2..1..1
%e A205818 ..2..0..2..2....1..1..1..0....0..2..0..2....2..0..2..2....1..0..0..2
%e A205818 ..2..1..1..0....2..0..2..0....0..1..1..1....2..1..1..0....1..2..1..2
%Y A205818 Cf. A205823.
%K A205818 nonn
%O A205818 1,1
%A A205818 _R. H. Hardin_, Feb 01 2012