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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.

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: A137067 A214200 A008555 * A164805 A152918 A055877

Adjacent sequences:  A056438 A056439 A056440 * A056442 A056443 A056444

KEYWORD

nonn

AUTHOR

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

STATUS

approved

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Last modified September 14 21:54 EDT 2014. Contains 246769 sequences.