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A056444 Number of primitive (period n) step cyclic shifted sequence structures using exactly two different symbols. 0
0, 1, 1, 2, 2, 5, 4, 10, 9, 22, 14, 78, 36, 124, 180, 343, 260, 1329, 804, 3732, 4428, 9742, 8384, 47364, 33778, 108292, 138756, 408244, 331184, 2251604, 1155734 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

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. Identical to A056439 for n>1.

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..31.

FORMULA

a(n) = A056439(n) - A000007(n-1).

CROSSREFS

Cf. A056424.

Sequence in context: A292385 A095057 A056439 * A319925 A112472 A240412

Adjacent sequences:  A056441 A056442 A056443 * A056445 A056446 A056447

KEYWORD

nonn

AUTHOR

Marks R. Nester

STATUS

approved

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Last modified August 20 20:50 EDT 2019. Contains 326155 sequences. (Running on oeis4.)