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%I #7 Sep 30 2023 16:37:31
%S 3,7,10,17,34,65,121,244,502,1023,2112,4430,9384,20081,43341,94137,
%T 205643,451538,995569,2202392,4885309,10860185,24185234,53936572,
%U 120423583,269112504,601825056,1346656482,3014688479,6751281413
%N Number of n X 3 0..1 arrays with every element unequal to 0, 1, 3, 4 or 8 king-move adjacent elements, with upper left element zero.
%C Column 3 of A305252.
%H R. H. Hardin, <a href="/A305247/b305247.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-1) +a(n-2) +a(n-4) -4*a(n-5) -a(n-6) -10*a(n-7) -10*a(n-8) -3*a(n-9) +6*a(n-11) +2*a(n-12).
%e Some solutions for n=5:
%e ..0..0..0. .0..1..1. .0..1..1. .0..0..1. .0..0..0. .0..1..1. .0..1..1
%e ..0..0..0. .1..1..1. .1..1..1. .0..0..0. .0..0..1. .1..1..1. .0..0..1
%e ..0..0..0. .1..1..1. .1..1..1. .0..0..0. .0..1..1. .1..1..1. .0..0..0
%e ..0..1..0. .0..1..1. .1..1..1. .0..0..0. .1..1..1. .1..1..0. .0..0..0
%e ..0..0..0. .0..0..1. .0..1..1. .0..0..0. .1..1..1. .1..0..0. .0..0..0
%Y Cf. A305252.
%K nonn
%O 1,1
%A _R. H. Hardin_, May 28 2018
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