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%I #4 May 13 2018 10:38:01
%S 4,21,41,117,316,810,2208,6012,15837,42579,115618,309144,829935,
%T 2246106,6045980,16264045,43945153,118607081,319754491,863718047,
%U 2333646132,6300949455,17025299379,46023642233,124382811126,336236258224
%N Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 3 or 6 king-move adjacent elements, with upper left element zero.
%C Column 3 of A304472.
%H R. H. Hardin, <a href="/A304467/b304467.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) +8*a(n-3) -21*a(n-4) -26*a(n-5) +10*a(n-6) +31*a(n-7) +20*a(n-8) -20*a(n-9) -10*a(n-10) for n>12
%e Some solutions for n=5
%e ..0..1..0. .0..0..1. .0..0..0. .0..0..1. .0..1..0. .0..1..1. .0..1..1
%e ..1..1..1. .0..0..0. .0..0..0. .0..1..1. .0..1..1. .0..1..1. .0..1..0
%e ..1..1..0. .1..1..0. .0..0..0. .1..1..1. .0..0..0. .0..1..1. .0..0..0
%e ..1..0..0. .1..0..0. .0..0..0. .1..1..1. .0..0..0. .1..0..1. .1..0..0
%e ..1..1..1. .0..0..0. .0..0..0. .0..1..1. .1..0..1. .0..1..1. .1..1..0
%Y Cf. A304472.
%K nonn
%O 1,1
%A _R. H. Hardin_, May 13 2018