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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
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]
FORMULA
sum mu(d)*A056431(n/d) where d|n.
CROSSREFS
Cf. A056421.
Sequence in context: A214200 A273924 A008555 * A365085 A164805 A275285
KEYWORD
nonn
STATUS
approved