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Number of squarefree words of length n in a 6-ary alphabet, with new values 0..5 introduced in increasing order.
0

%I #6 Mar 22 2023 14:39:51

%S 1,1,2,4,12,40,153,638,2825,12938,60458,285664,1358283,6480694,

%T 30979999,148249768,709832688,3399805736,16286469156,78026226228,

%U 373832145200,1791120945112

%N Number of squarefree words of length n in a 6-ary alphabet, with new values 0..5 introduced in increasing order.

%C Column 5 of A215075.

%e Some solutions for n=9

%e ..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0

%e ..1....1....1....1....1....1....1....1....1....1....1....1....1....1....1....1

%e ..2....2....2....2....2....2....2....2....2....2....0....2....0....2....2....2

%e ..3....1....0....3....0....3....3....0....3....0....2....0....2....3....0....3

%e ..4....3....3....0....3....4....2....3....1....3....1....3....1....4....3....4

%e ..3....2....0....2....2....5....0....0....2....0....3....4....2....2....4....2

%e ..5....4....2....4....3....3....2....4....4....2....0....3....0....3....1....0

%e ..0....3....4....3....4....4....1....3....5....4....1....2....1....0....0....2

%e ..3....4....2....5....3....1....4....5....4....0....3....0....0....2....2....3

%Y Cf. A215075.

%K nonn

%O 1,3

%A _R. H. Hardin_, Aug 02 2012