A221726 - OEIS

%I #7 Jan 22 2013 19:37:14

%S 0,16,0,464,0,13948,0,420736,0,12695288,0,383074904,0,11559126552,0,

%T 348791805904,0,10524646286488,0,317576778411352,0,9582745781519416,0,

%U 289155325092787296,0,8725140362031620984,0,263277441988312544616,0

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

%C Column 3 of A221728

%H R. H. Hardin, <a href="/A221726/b221726.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 44*a(n-2) -462*a(n-4) +1400*a(n-6) -1417*a(n-8) -448*a(n-10) -280*a(n-12) +100*a(n-14)

%e Some solutions for n=4

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

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

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

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

%K nonn

%O 1,2

%A _R. H. Hardin_ Jan 22 2013