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Number of nX3 0..1 arrays with every element unequal to 0, 1, 5 or 8 king-move adjacent elements, with upper left element zero.
1

%I #4 May 09 2018 10:11:31

%S 3,3,6,10,19,37,67,124,235,436,808,1513,2821,5245,9784,18247,33982,

%T 63334,118075,220021,410023,764248,1424311,2654380,4947124,9220057,

%U 17183197,32024569,59684740,111234331,207308038,386362258,720065251,1341989365

%N Number of nX3 0..1 arrays with every element unequal to 0, 1, 5 or 8 king-move adjacent elements, with upper left element zero.

%C Column 3 of A304270.

%H R. H. Hardin, <a href="/A304265/b304265.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +3*a(n-3) for n>4

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A304270.

%K nonn

%O 1,1

%A _R. H. Hardin_, May 09 2018