1,2

See A056371 for an explanation of step shifts. Permuting the symbols will not change the structure.

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

Use de Bruijn's generalization of Polya's enumeration theorem as discussed in reference.

Cf. A056371.

Sequence in context: A102625 A117777 A049297 this_sequence A056430 A089878 A057545

Adjacent sequences: A056388 A056389 A056390 this_sequence A056392 A056393 A056394

nonn

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