%I #4 Jan 11 2013 10:44:59

%S 1,137,2856,66077,1534835,36054361,849482126,20037479191,472778990849,

%T 11155734923302,263229189709284,6210988381194727,146547761557950631,

%U 3457733626802911867,81582980136833112390,1924884328527038591459

%N Number of 3Xn arrays of occupancy after each element stays put or moves to some horizontal, diagonal or antidiagonal neighbor, with no occupancy greater than 2

%C Row 3 of A221345

%H R. H. Hardin, <a href="/A221346/b221346.txt">Table of n, a(n) for n = 1..18</a>

%e Some solutions for n=3

%e ..2..2..0....1..1..2....1..1..0....2..1..2....0..2..2....0..1..1....1..2..1

%e ..2..0..1....0..1..1....1..1..0....0..0..0....1..0..0....1..2..2....1..1..1

%e ..0..2..0....1..0..2....2..1..2....1..2..1....1..2..1....1..1..0....1..0..1

%K nonn

%O 1,2

%A _R. H. Hardin_ Jan 11 2013