%I A056315
%S A056315 4,6,36,126,540,2034,8316,32760,131544,524250,2099196,8388450,33562620,
%T A056315 134217594,536903100,2147483520,8590065660,34359735816,137439477756,
%U A056315 549755813250,2199025344348,8796093020154
%N A056315 Number of primitive (aperiodic) reversible strings with n beads using 
               a maximum of four different colors.
%C A056315 A string and its reverse are considered to be equivalent.
%D A056315 M. R. Nester (1999). Mathematical investigations of some plant interaction 
               designs. PhD Thesis. University of Queensland, Brisbane, Australia.
%F A056315 Sum mu(d)*A032121(n/d) where d|n.
%Y A056315 Cf. A045625, A056314.
%Y A056315 Sequence in context: A137021 A092187 A092765 this_sequence A103234 A074061 
               A125081
%Y A056315 Adjacent sequences: A056312 A056313 A056314 this_sequence A056316 A056317 
               A056318
%K A056315 nonn
%O A056315 1,1
%A A056315 Marks R. Nester (nesterm(AT)dpi.qld.gov.au)