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%I #9 Apr 04 2018 10:48:33
%S 33,161,730,3435,15887,74148,344483,1604473,7462786,34738575,
%T 161631659,752241404,3500410439,16290047469,75805472562,352771994195,
%U 1641641366551,7639557462868,35551227927131,165441007206577,769893052530306
%N Half the number of (n+1) X 4 binary arrays with no 2 X 2 subblock having exactly 2 ones.
%C Column 3 of A183782.
%H R. H. Hardin, <a href="/A183776/b183776.txt">Table of n, a(n) for n = 1..200</a>
%F Empirical: a(n) = 2*a(n-1) + 18*a(n-2) - 13*a(n-3) - 70*a(n-4) + 24*a(n-5) + 64*a(n-6).
%F Empirical g.f.: x*(33 + 95*x - 186*x^2 - 494*x^3 + 280*x^4 + 512*x^5) / ((1 + 2*x)*(1 - 4*x - 10*x^2 + 33*x^3 + 4*x^4 - 32*x^5)). - _Colin Barker_, Apr 04 2018
%e Some solutions with a(1,1)=0 for 3 X 4:
%e ..0..1..1..1....0..0..0..0....0..0..0..0....0..0..0..0....0..1..0..1
%e ..0..0..1..0....0..0..0..0....0..1..0..1....0..0..1..0....0..0..0..0
%e ..0..0..0..0....0..1..0..0....0..0..0..0....1..0..0..0....1..0..1..0
%Y Cf. A183782.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 07 2011
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