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%I #9 Jun 28 2018 08:25:43
%S 9,81,169,361,841,2025,5041,12769,32761,84681,219961,573049,1495729,
%T 3908529,10220809,26739241,69973225,183142089,479391025,1254930625,
%U 3285238489,8600522121,22515902809,58946498521,154322479921,404019140625
%N Number of n X 4 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 1 and 1 1 0 vertically.
%C Column 4 of A208108.
%H R. H. Hardin, <a href="/A208104/b208104.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) - 2*a(n-2) - 6*a(n-3) + 4*a(n-4) + 2*a(n-5) - a(n-6) for n>7.
%F Empirical g.f.: x*(9 + 45*x - 137*x^2 - 99*x^3 + 185*x^4 + 55*x^5 - 40*x^6) / ((1 - x)*(1 + x)*(1 - 3*x + x^2)*(1 - x - x^2)). - _Colin Barker_, Jun 28 2018
%e Some solutions for n=10:
%e ..1..1..0..1....1..1..0..1....0..1..1..1....0..1..1..0....0..0..1..1
%e ..0..1..1..1....1..1..0..0....0..1..1..0....0..1..1..1....1..1..1..0
%e ..1..1..0..1....1..1..0..1....0..1..1..1....1..1..1..0....0..0..1..1
%e ..0..1..1..1....1..1..0..0....0..1..1..0....0..1..1..0....0..1..1..0
%e ..1..1..0..1....1..1..1..1....1..1..1..1....1..1..1..1....1..0..1..1
%e ..0..1..1..1....1..1..0..0....0..1..1..0....0..1..1..0....0..1..1..0
%e ..1..1..0..1....1..1..1..1....1..1..1..1....1..1..1..1....1..0..1..1
%e ..0..1..1..1....1..1..0..0....0..1..1..0....0..1..1..0....0..1..1..0
%e ..1..1..0..1....1..1..0..1....1..1..1..0....0..1..1..1....1..0..1..1
%e ..0..1..1..1....1..1..0..0....0..1..1..0....1..1..1..0....0..1..1..0
%Y Cf. A208108.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 23 2012
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