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A207769 Number of n X 3 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 0 1 0 vertically.

%I A207769 #8 Jun 25 2018 16:05:46
%S A207769 6,36,84,192,450,972,2040,4278,8910,18462,38214,79044,163386,337638,
%T A207769 697668,1441488,2978208,6153084,12712374,26263824,54261060,112103226,
%U A207769 231604842,478494570,988567506,2042375592,4219537710,8717543538
%N A207769 Number of n X 3 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 0 1 0 vertically.
%C A207769 Column 3 of A207774.
%H A207769 R. H. Hardin, <a href="/A207769/b207769.txt">Table of n, a(n) for n = 1..210</a>
%F A207769 Empirical: a(n) = 3*a(n-1) - 2*a(n-2) + a(n-3) - 2*a(n-4) + a(n-6) for n>7.
%F A207769 Empirical g.f.: 6*x*(1 + 3*x - 2*x^2 + x^3 + 3*x^4 - x^5 - x^6) / ((1 - x)^2*(1 - x - x^2 - 2*x^3 - x^4)). - _Colin Barker_, Jun 25 2018
%e A207769 Some solutions for n=4:
%e A207769 ..1..1..0....0..1..0....1..1..0....0..0..1....0..0..1....1..1..0....1..1..0
%e A207769 ..1..0..1....1..0..0....1..1..0....1..0..0....0..1..1....1..1..0....0..1..0
%e A207769 ..1..0..1....1..1..0....0..1..0....1..0..1....0..1..1....1..1..0....1..1..0
%e A207769 ..0..0..1....0..1..0....0..1..0....0..0..1....0..1..0....0..1..0....1..0..0
%Y A207769 Cf. A207774.
%K A207769 nonn
%O A207769 1,1
%A A207769 _R. H. Hardin_, Feb 20 2012