%I #3 Jan 14 2013 03:48:31
%S 0,1,4,25,189,1156,6996,43681,268632,1664100,10278914,63568729,
%T 392903168,2429109796
%N Number of 4Xn arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, with every occupancy equal to zero or two
%C Row 4 of A221381
%e All solutions for n=3
%e ..0..2..0....0..2..2....0..2..2....0..2..0
%e ..2..2..0....0..2..0....0..2..0....2..2..0
%e ..0..2..0....0..2..0....0..2..2....0..2..2
%e ..2..2..0....2..2..0....0..2..0....0..2..0
%K nonn
%O 1,3
%A _R. H. Hardin_ Jan 14 2013