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

%I #4 Aug 07 2018 21:56:14

%S 1,2,2,3,5,10,23,54,131,321,789,1943,4788,11802,29094,71725,176826,

%T 435938,1074743,2649629,6532294,16104471,39703358,97883171,241317505,

%U 594935145,1466730843,3616023336,8914808626,21978235610,54184319689

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

%C Column 2 of A317815.

%H R. H. Hardin, <a href="/A317809/b317809.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) +a(n-2) +a(n-3) -a(n-4) -a(n-5) -a(n-6)

%e All solutions for n=5

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

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

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

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

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

%Y Cf. A317815.

%K nonn

%O 1,2

%A _R. H. Hardin_, Aug 07 2018