%I #4 Feb 01 2013 12:23:20
%S 1,489,24535,1759041,119035112,8118923949,552777330287,37650441405451,
%T 2564181255574899,174635497977344862,11893675692936218866,
%U 810026663520753630706,55167419097633745309553,3757214394165203187203557
%N Number of 4Xn arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, without move-in move-out straight through or left turns
%C Row 4 of A221937
%H R. H. Hardin, <a href="/A221940/b221940.txt">Table of n, a(n) for n = 1..24</a>
%e Some solutions for n=3
%e ..1..3..0....0..1..1....2..0..1....1..0..1....0..1..1....0..1..0....1..1..0
%e ..0..0..1....3..0..1....1..0..0....1..3..0....3..0..1....2..3..0....1..4..0
%e ..1..2..0....0..2..0....2..3..0....0..1..1....1..1..3....1..1..2....0..2..0
%e ..2..1..1....2..1..1....1..1..1....2..1..1....0..1..0....1..0..1....0..2..1
%K nonn
%O 1,2
%A _R. H. Hardin_ Feb 01 2013