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%I #9 Mar 29 2018 08:49:13
%S 3,15,39,135,495,1647,5751,20223,70119,244863,855927,2985903,10426887,
%T 36416223,127148535,444006927,1550518119,5414352255,18907098327,
%U 66024403695,230558764743,805118884191,2811503074743,9817858453455
%N Number of n X 2 0..2 arrays with every element equal to either the sum mod 3 of its vertical neighbors or the sum mod 3 of its horizontal neighbors.
%C Column 2 of A183483.
%H R. H. Hardin, <a href="/A183476/b183476.txt">Table of n, a(n) for n = 1..200</a>
%F Empirical: a(n) = 3*a(n-1) + 12*a(n-3) - 18*a(n-4) - 36*a(n-6).
%F Empirical g.f.: 3*x*(1 + 2*x - 2*x^2 - 6*x^3 - 12*x^4 - 12*x^5) / ((1 - 6*x^3)*(1 - 3*x - 6*x^3)). - _Colin Barker_, Mar 29 2018
%e Some solutions for 4 X 2.
%e ..2..2....2..2....1..1....0..0....2..2....0..0....0..0....2..2....0..0....1..1
%e ..0..0....2..2....0..2....0..0....1..1....1..1....2..0....0..0....2..2....1..1
%e ..1..1....0..0....2..1....1..1....0..0....1..1....2..0....2..2....1..1....2..2
%e ..0..0....1..1....2..2....0..0....2..2....1..1....0..0....2..2....1..1....0..0
%Y Cf. A183483.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 05 2011
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