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A207347 Number of 3 X n 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 0 and 1 1 1 vertically. 1

%I

%S 6,36,84,192,426,858,1704,3330,6390,12150,22938,43044,80424,149766,

%T 278160,515568,954072,1763304,3255666,6006342,11074116,20407650,

%U 37592934,69228330,127454070,234605316,431771328,794539482,1461954876,2689788048

%N Number of 3 X n 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 0 and 1 1 1 vertically.

%C Row 3 of A207346.

%H R. H. Hardin, <a href="/A207347/b207347.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) + a(n-3) - 2*a(n-4) - a(n-5) - a(n-6) for n>7.

%F Empirical g.f.: 6*x*(1 + x)*(1 + 3*x - x^2 + 4*x^3 - x^4 + x^5) / ((1 - x - x^3)*(1 - x - x^2 - x^3)). - _Colin Barker_, Jun 22 2018

%e Some solutions for n=4:

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

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

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

%Y Cf. A207346.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 17 2012

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Last modified January 20 03:25 EST 2022. Contains 350467 sequences. (Running on oeis4.)