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%I #4 Jan 09 2013 16:27:57
%S 17,1001,63285,4119299,270434991,17788952657,1170461488239,
%T 77011254247993,5066792859597385,333350527345443633,
%U 21931251172817255263,1442854892820284178311,94924922041346379554607
%N Number of nX4 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, with no occupancy greater than 2
%C Column 4 of A221303
%H R. H. Hardin, <a href="/A221299/b221299.txt">Table of n, a(n) for n = 1..101</a>
%e Some solutions for n=3
%e ..0..1..2..2....2..1..0..2....0..1..1..0....1..0..0..2....2..1..2..0
%e ..2..0..1..2....0..1..1..0....1..1..2..2....1..1..0..2....0..1..2..1
%e ..1..1..0..0....1..1..2..1....1..1..1..1....1..2..2..0....2..0..0..1
%K nonn
%O 1,1
%A _R. H. Hardin_ Jan 09 2013