A221721 - OEIS

%I #5 Jan 22 2013 19:13:31

%S 8,318,11733,429160,15672482,572137641,20884488408,762319022830,

%T 27825750505059,1015678516372760,37073658380751658,

%U 1353239190373176421,49395077915916094348,1802987762537953450798,65811514041618097318227

%N Number of nX3 arrays of occupancy after each element stays put or moves to some horizontal, diagonal or antidiagonal neighbor

%C Column 3 of A221723

%H R. H. Hardin, <a href="/A221721/b221721.txt">Table of n, a(n) for n = 1..18</a>

%F Empirical: a(n) = 48*a(n-1) -430*a(n-2) +313*a(n-3) +2310*a(n-4) -1178*a(n-5) -878*a(n-6) +2386*a(n-7) +364*a(n-8)

%e Some solutions for n=3

%e ..1..2..0....2..1..0....0..2..3....1..0..2....1..2..2....1..1..0....2..1..0

%e ..0..1..0....1..1..0....0..2..1....2..1..0....1..1..1....0..0..3....0..2..3

%e ..0..5..0....0..2..2....0..1..0....1..1..1....1..0..0....1..2..1....0..1..0

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 22 2013