%I
%S 0,64,112,58081,1319409,103489929,4085800416,226720727104,
%T 10445351809532,530909339760900,25591483232781872,1268920553028932644,
%U 61970903049203536750,3051063081822723807844,149565983362653741790314
%N Number of 4Xn arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2
%C Row 4 of A221255
%H R. H. Hardin, <a href="/A221258/b221258.txt">Table of n, a(n) for n = 1..16</a>
%e Some solutions for n=3
%e ..1..2..1....0..2..0....1..2..0....0..2..1....1..2..0....0..2..1....0..2..0
%e ..0..2..0....1..2..0....0..2..2....1..2..1....1..2..0....0..2..1....1..2..0
%e ..0..2..1....2..2..0....0..2..0....0..2..1....0..2..2....1..2..0....1..2..1
%e ..1..2..0....0..2..1....0..2..1....0..2..0....0..2..0....0..2..1....1..2..0
%K nonn
%O 1,2
%A _R. H. Hardin_ Jan 06 2013
