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A056440
Number of primitive (period n) step cyclic shifted sequence structures using a maximum of three different symbols.
2
1, 1, 2, 4, 5, 18, 15, 60, 80, 293, 295, 2217, 1777, 9763, 20632, 58362, 79553, 600696, 567543, 3671674, 6935728, 23785615, 31017007, 246154210, 282456327, 1357925621, 2615206650, 11358502734
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)*A056430(n/d) where d divides n.
CROSSREFS
Cf. A056420.
Sequence in context: A092051 A065063 A276311 * A101843 A192117 A084592
KEYWORD
nonn
STATUS
approved