%I #6 Aug 22 2017 20:53:09
%S 1,1,3,9,31,111,454,1982,9130,43547,211658,1041316,5156641,25640000,
%T 127773440,637622320,3184387573,15910938734,79521737938,397510683092,
%U 1987259549544,9935420434636,49674470817194
%N Number of primitive (aperiodic) reversible string structures with n beads using a maximum of five different colors.
%C A string and its reverse are considered to be equivalent. Permuting the colors will not change the structure.
%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)*A056324(n/d) where d|n.
%Y Cf. A056316.
%K nonn
%O 1,3
%A _Marks R. Nester_
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