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Number of length-n 0..6 arrays connected end-around, with no sequence of L<n elements immediately followed by itself (periodic "squarefree").
0

%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