%I #8 Dec 12 2015 01:47:56
%S 5,20,60,240,720,2940,10080,38640,140400,529440,1956900,7335840,
%T 27285180,101960040,380209980,1419732000
%N Number of length-n 0..4 arrays connected end-around, with no sequence of L<n elements immediately followed by itself (periodic "squarefree").
%C Column 4 of A215228.
%e Some solutions for n=8:
%e ..2....2....1....4....4....3....3....1....0....0....1....1....4....4....4....4
%e ..3....4....4....0....0....1....4....3....4....1....4....3....0....2....2....1
%e ..2....0....3....2....4....2....2....4....1....0....3....0....3....3....1....3
%e ..0....4....1....3....3....0....1....3....3....3....1....4....2....2....4....0
%e ..1....3....2....4....0....1....3....0....2....2....3....3....1....1....0....3
%e ..2....0....3....3....1....3....2....2....4....0....0....0....4....0....2....1
%e ..4....2....0....1....0....0....0....4....3....1....3....2....3....2....0....0
%e ..0....1....3....2....2....2....1....2....2....3....2....4....2....0....3....2
%K nonn,more
%O 1,1
%A _R. H. Hardin_, Aug 06 2012