%I #6 Aug 22 2017 20:53:07
%S 0,0,0,0,0,720,15120,191520,1905120,16435440,129230640,953028720,
%T 6711344640,45674173440,302899156560,1969146930240,12604139926560,
%U 79694818842240,499018753280880,3100376788241040
%N Number of primitive (aperiodic) words of length n which contain exactly six different symbols.
%D M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2]
%F Sum mu(d)*A000920(n/d) where d|n.
%Y Cf. A000400, A000920, A054721.
%K nonn
%O 1,6
%A _Marks R. Nester_