%I #4 Jan 15 2013 20:10:58
%S 0,8,0,226,0,6798,0,198823,0,5789134,0,168353683,0,4894400220,0,
%T 142279944512,0,4135993312056,0,120230312311224,0,3495003621811704,0,
%U 101597065323229956,0,2953348289319127152,0,85851554285154067136,0
%N Number of 3Xn arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, with every occupancy equal to zero or two
%C Row 3 of A221419
%H R. H. Hardin, <a href="/A221421/b221421.txt">Table of n, a(n) for n = 1..202</a>
%F Empirical: a(n) = 36*a(n-2) -200*a(n-4) -40*a(n-6) -84*a(n-8) +80*a(n-10) -20*a(n-12) +80*a(n-14) for n>20
%e Some solutions for n=4
%e ..0..2..0..2....0..2..2..0....2..2..0..0....0..2..0..0....0..2..0..0
%e ..0..2..2..0....2..2..0..2....0..0..2..0....2..2..2..0....2..0..2..0
%e ..0..0..2..2....0..0..2..0....2..2..0..2....0..0..2..2....2..2..2..0
%K nonn
%O 1,2
%A _R. H. Hardin_ Jan 15 2013
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