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A288628 Number of step cyclic shifted sequence structures of length n using an infinite alphabet. 2
1, 2, 3, 7, 8, 37, 37, 223, 468, 3203, 6398, 93103, 178663, 2282131, 11561896, 82120878, 304719416, 6316222138, 17055376113, 323332552319, 1884432112761, 20485110860448, 87256977757852, 2322728266726152, 9277181270824996, 159074512149044084, 1122874592283076868 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

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..27.

PROG

(PARI) \\ see A056391 for Polya enumeration functions

a(n) = NonequivalentStructs(CyclicStepShiftPerms(n), n); \\ Andrew Howroyd, Oct 14 2017

CROSSREFS

Row sums of A288627.

Cf. A056391, A056371, A288621.

Sequence in context: A056432 A271506 A056433 * A064669 A068342 A038034

Adjacent sequences:  A288625 A288626 A288627 * A288629 A288630 A288631

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Jun 11 2017

STATUS

approved

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Last modified March 8 20:52 EST 2021. Contains 341953 sequences. (Running on oeis4.)