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%I #8 Dec 12 2015 01:47:23
%S 7,42,210,1260,6720,40110,228480,1338120,7761600,45291120,263674950,
%T 1537291560
%N Number of length-n 0..6 arrays connected end-around, with no sequence of L<n elements immediately followed by itself (periodic "squarefree").
%C Column 6 of A215228.
%e Some solutions for n=5:
%e ..6....4....6....0....4....3....0....2....2....4....4....2....0....2....3....0
%e ..3....3....4....2....5....0....1....4....5....3....3....6....4....3....6....3
%e ..6....4....6....1....0....2....4....6....0....5....2....4....5....0....0....1
%e ..4....5....5....5....3....5....5....0....5....0....3....5....6....6....6....4
%e ..1....6....1....2....6....6....3....4....3....5....0....3....3....0....5....6
%K nonn,more
%O 1,1
%A _R. H. Hardin_, Aug 06 2012