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%I #4 Mar 07 2018 07:29:41
%S 2,3,2,3,6,6,11,26,43,82,178,347,682,1403,2822,5638,11411,23026,46291,
%T 93346,188258,379187,764178,1540467,3104262,6255878,12608667,25410698,
%U 51210491,103208946,208003346,419198091,844835898,1702649067,3431439878
%N Number of nX2 0..1 arrays with every element equal to 0, 1, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
%C Column 2 of A300506.
%H R. H. Hardin, <a href="/A300500/b300500.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-1) -a(n-2) +4*a(n-3) -4*a(n-4) +a(n-5) -2*a(n-6) +a(n-7)
%e All solutions for n=5
%e ..0..1. .0..1. .0..1. .0..1. .0..1. .0..0
%e ..0..0. .0..0. .0..1. .1..0. .0..1. .1..1
%e ..0..0. .0..0. .1..1. .0..1. .1..1. .0..0
%e ..0..1. .0..0. .1..1. .1..0. .1..0. .1..1
%e ..0..1. .1..0. .0..1. .0..1. .1..0. .0..0
%Y Cf. A300506.
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 07 2018