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Number of nX2 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
4

%I #4 Mar 08 2018 12:21:56

%S 1,3,5,16,40,113,304,833,2270,6194,16900,46103,125787,343166,936250,

%T 2554294,6968726,19012299,51870004,141513486,386081850,1053321508,

%U 2873707154,7840144587,21389746215,58356225385,159209417569,434360490031

%N Number of nX2 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

%C Column 2 of A300539.

%H R. H. Hardin, <a href="/A300533/b300533.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +4*a(n-2) +2*a(n-3) -a(n-6)

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A300539.

%K nonn

%O 1,2

%A _R. H. Hardin_, Mar 08 2018