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Number of nX3 0..1 arrays with every element unequal to 0, 1 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
1

%I #4 Aug 06 2018 12:10:50

%S 3,4,5,11,16,28,44,74,122,209,344,584,981,1670,2806,4758,8047,13665,

%T 23111,39195,66419,112700,190989,323943,549302,931821,1580102,2680148,

%U 4545629,7710521,13077362,22181756,37623572,63817667,108244170,183603356

%N Number of nX3 0..1 arrays with every element unequal to 0, 1 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

%C Column 3 of A317773.

%H R. H. Hardin, <a href="/A317768/b317768.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +6*a(n-4) -2*a(n-5) -11*a(n-8) -3*a(n-9) +6*a(n-12) +4*a(n-13) -a(n-16) -a(n-17) for n>23

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A317773.

%K nonn

%O 1,1

%A _R. H. Hardin_, Aug 06 2018