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%I #6 Aug 12 2016 06:54:16
%S 0,2,2,30,58,588,2388,17456,102874,731154,5027962,36610288,266876496,
%T 1982397806,14796809106,111298650288,840466993090,6372988144620,
%U 48466708273020,369602842446350,2824995007935614,21637397279211678
%N Number of 3Xn arrays containing n copies of 0..3-1 with every element equal to at least one horizontal neighbor and the top left element equal to 0.
%C Row 3 of A267724.
%H R. H. Hardin, <a href="/A267726/b267726.txt">Table of n, a(n) for n = 1..38</a>
%e Some solutions for n=4
%e ..0..0..0..0....0..0..2..2....0..0..1..1....0..0..0..0....0..0..2..2
%e ..2..2..1..1....1..1..0..0....1..1..2..2....2..2..1..1....1..1..1..1
%e ..1..1..2..2....1..1..2..2....2..2..0..0....2..2..1..1....0..0..2..2
%Y Cf. A267724.
%K nonn
%O 1,2
%A _R. H. Hardin_, Jan 20 2016
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