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%I #4 Mar 11 2014 12:01:47
%S 7,42,252,1470,8610,50190,292740,1706250,9946020,57970080,337883700,
%T 1969343880,11478292770,66900843240,389929523550,2272690998690
%N Number of squarefree words of length n in a 7-ary alphabet
%C Column 6 of A214943
%e Some solutions for n=6
%e ..0....4....4....4....5....2....4....4....2....3....6....0....0....6....2....5
%e ..4....1....6....0....1....5....1....1....0....5....4....5....1....0....1....0
%e ..2....5....2....6....6....2....0....5....6....0....6....4....5....5....6....5
%e ..3....0....6....5....0....1....3....4....2....3....2....2....3....3....3....2
%e ..6....4....0....6....4....5....1....5....5....2....3....4....1....2....2....5
%e ..4....0....6....4....6....2....0....6....2....1....4....6....5....4....6....0
%K nonn
%O 1,1
%A _R. H. Hardin_ Jul 30 2012