1,3

Permuting the alphabet will not change a word structure. Thus aabc and bbca have the same structure. This is identical to A000740 for n>1.

M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia.

Sum mu(d)*A000225(n/d-1) where d|n and n>0.

Cf. A056267.

Sequence in context: A020991 A079825 A134774 this_sequence A000740 A069712 A076971

Adjacent sequences: A056275 A056276 A056277 this_sequence A056279 A056280 A056281

nonn

Marks R. Nester (nesterm(AT)dpi.qld.gov.au)