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%I #4 Dec 25 2012 19:50:59
%S 2,208,7551,291080,11115933,424939090,16241930112,620799451653,
%T 23728084357764,906930211627870,34664497553698238,1324939111423377826,
%U 50641541794670836181,1935610258239045700193,73982484134692519016233
%N Number of nX3 arrays of occupancy after each element moves to some horizontal, vertical or antidiagonal neighbor
%C Column 3 of A220943
%H R. H. Hardin, <a href="/A220940/b220940.txt">Table of n, a(n) for n = 1..21</a>
%e Some solutions for n=3
%e ..0..0..0....0..1..1....2..2..0....0..2..0....2..1..1....2..1..0....0..3..2
%e ..3..2..2....1..1..0....0..4..1....1..0..1....0..0..1....0..1..3....0..1..1
%e ..1..0..1....3..2..0....0..0..0....3..2..0....1..3..0....1..0..1....0..2..0
%K nonn
%O 1,1
%A _R. H. Hardin_ Dec 25 2012