

A056441


Number of primitive (period n) step cyclic shifted sequence structures using a maximum of four different symbols.


2



1, 1, 2, 5, 6, 29, 28, 142, 242, 1222, 1664, 15935, 18198, 134452, 376424, 1415060, 2634596, 26534337, 33499358, 287001476, 727425470, 3332039278, 5794658930, 61120838930, 93825569002, 601444720052
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OFFSET

1,3


COMMENTS

See A056371 for an explanation of step shifts. Under step cyclic shifts, abcde, bdace, bcdea, cdeab and daceb etc. are equivalent. Permuting the symbols will not change the structure.


REFERENCES

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


LINKS

Table of n, a(n) for n=1..26.


FORMULA

sum mu(d)*A056431(n/d) where dn.


CROSSREFS

Cf. A056421.
Sequence in context: A214200 A273924 A008555 * A164805 A275285 A152918
Adjacent sequences: A056438 A056439 A056440 * A056442 A056443 A056444


KEYWORD

nonn


AUTHOR

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


STATUS

approved



