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Number of 3Xn 0..1 arrays with every element equal to 0, 1, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
1

%I #4 Apr 21 2018 12:49:14

%S 4,4,12,17,24,67,158,298,595,1337,2863,5840,12231,26168,55140,115193,

%T 242621,512713,1078852,2267487,4776110,10063518,21181387,44579665,

%U 93874659,197672892,416137435,876080072,1844597384,3883701257,8176491213

%N Number of 3Xn 0..1 arrays with every element equal to 0, 1, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

%C Row 3 of A303314.

%H R. H. Hardin, <a href="/A303315/b303315.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +3*a(n-3) +4*a(n-4) for n>7

%e Some solutions for n=5

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

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

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

%Y Cf. A303314.

%K nonn

%O 1,1

%A _R. H. Hardin_, Apr 21 2018