%I #5 Jan 11 2013 10:42:38
%S 7,137,2856,60807,1299057,27767394,593562702,12688126159,271223239234,
%T 5797699341153,123932233563380,2649188126866350,56629314186026164,
%U 1210513943745878094,25876068208481143920,553129442930337241907
%N Number of nX3 arrays of occupancy after each element stays put or moves to some horizontal, diagonal or antidiagonal neighbor, with no occupancy greater than 2
%C Column 3 of A221345
%H R. H. Hardin, <a href="/A221342/b221342.txt">Table of n, a(n) for n = 1..121</a>
%F Empirical: a(n) = 43*a(n-1) -604*a(n-2) +3305*a(n-3) -5534*a(n-4) -8103*a(n-5) +18838*a(n-6) +17434*a(n-7) -4723*a(n-8) -11537*a(n-9) -7289*a(n-10) -2900*a(n-11) -652*a(n-12) -296*a(n-13) -94*a(n-14) -16*a(n-15)
%e Some solutions for n=3
%e ..1..0..0....1..1..2....0..1..1....2..0..2....1..1..1....0..0..1....2..2..1
%e ..1..1..2....0..0..2....0..2..0....2..2..1....0..0..1....0..1..2....0..1..0
%e ..0..2..2....0..1..2....2..2..1....0..0..0....1..2..2....2..2..1....1..0..2
%K nonn
%O 1,1
%A _R. H. Hardin_ Jan 11 2013