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A221406 Number of nX5 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, with every occupancy equal to zero or two.

%I A221406 #6 Jul 23 2025 01:53:07
%S A221406 0,120,0,47156,0,18852560,0,7505597654,0,2984164922226,0,
%T A221406 1185951960926210,0,471249297474390114,0,187247029623260170674,0,
%U A221406 74400007192624944055794,0,29561675588644660921885852,0
%N A221406 Number of nX5 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, with every occupancy equal to zero or two.
%C A221406 Column 5 of A221408
%H A221406 R. H. Hardin, <a href="/A221406/b221406.txt">Table of n, a(n) for n = 1..28</a>
%e A221406 Some solutions for n=4
%e A221406 ..2..0..2..2..2....0..2..0..2..2....2..0..2..2..2....2..0..0..2..2
%e A221406 ..0..0..2..0..0....0..2..0..2..0....0..0..0..2..0....0..2..0..0..2
%e A221406 ..2..0..0..0..2....0..0..0..2..0....0..2..0..2..0....2..0..2..2..0
%e A221406 ..2..0..2..0..2....2..2..2..2..0....2..0..2..2..0....2..0..0..0..2
%K A221406 nonn
%O A221406 1,2
%A A221406 _R. H. Hardin_ Jan 15 2013