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%I A304128 #4 May 07 2018 07:55:08
%S A304128 3,7,9,19,33,53,89,155,261,439,749,1271,2149,3647,6189,10487,17781,
%T A304128 30159,51133,86695,147013,249279,422669,716695,1215253,2060591,
%U A304128 3493981,5924487,10045669,17033631,28882605,48973943,83041205,140806415,238754301
%N A304128 Number of nX3 0..1 arrays with every element unequal to 0, 1, 3 or 6 king-move adjacent elements, with upper left element zero.
%C A304128 Column 3 of A304133.
%H A304128 R. H. Hardin, <a href="/A304128/b304128.txt">Table of n, a(n) for n = 1..210</a>
%F A304128 Empirical: a(n) = a(n-1) +2*a(n-3) for n>7
%e A304128 Some solutions for n=5
%e A304128 ..0..1..1. .0..0..1. .0..0..0. .0..1..1. .0..0..1. .0..1..1. .0..0..1
%e A304128 ..1..1..1. .0..1..1. .0..0..1. .1..1..1. .0..0..0. .0..0..1. .0..1..1
%e A304128 ..1..1..1. .0..0..0. .0..1..1. .1..1..1. .0..0..0. .0..0..0. .1..1..1
%e A304128 ..1..1..0. .0..0..1. .1..1..1. .0..1..1. .0..0..0. .0..1..1. .1..1..1
%e A304128 ..1..0..0. .0..1..1. .1..1..1. .0..0..1. .0..0..0. .0..0..1. .1..1..1
%Y A304128 Cf. A304133.
%K A304128 nonn
%O A304128 1,1
%A A304128 _R. H. Hardin_, May 07 2018

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