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Number of 3Xn arrays containing n copies of 0..3-1 with no element plus any horizontal or vertical neighbor equal to 3-1.
1

%I #6 Aug 12 2016 06:53:58

%S 2,0,4,16,60,228,1024,4288,18172,76838,326264,1390048,5947760,

%T 25515274,109801760,473895774,2050771696,8896415264,38680996104,

%U 168532976250,735715851956,3217440736916,14093823129980,61831989407076

%N Number of 3Xn arrays containing n copies of 0..3-1 with no element plus any horizontal or vertical neighbor equal to 3-1.

%C Row 3 of A265663.

%H R. H. Hardin, <a href="/A265664/b265664.txt">Table of n, a(n) for n = 1..104</a>

%e Some solutions for n=4

%e ..0..0..0..1....0..1..0..0....2..2..2..1....2..2..1..0....1..0..1..2

%e ..1..0..1..2....1..2..1..0....1..2..1..0....2..1..0..0....0..1..2..2

%e ..2..1..2..2....2..2..2..1....0..1..0..0....1..2..1..0....0..0..1..2

%Y Cf. A265663.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 12 2015