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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 (list; graph; refs; listen; history; text; internal format)
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. [See A056391 for pdf file of Chap. 2]

LINKS

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

FORMULA

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

CROSSREFS

Cf. A056421.

Sequence in context: A214200 A273924 A008555 * A164805 A275285 A152918

Adjacent sequences:  A056438 A056439 A056440 * A056442 A056443 A056444

KEYWORD

nonn,changed

AUTHOR

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

STATUS

approved

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Last modified May 29 01:07 EDT 2017. Contains 287241 sequences.