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A288621
Number of step shifted (decimated) sequence structures of length n using an infinite alphabet.
2
1, 2, 4, 11, 18, 117, 162, 1205, 3621, 29271, 68086, 1069614, 2305158, 31825670, 172974370, 1311400891, 5179123522, 113680235941, 324041807958, 6466011855715, 39572612670818, 450671611457619, 2006909406239780, 55745145216877102, 231929517217884081
OFFSET
1,2
COMMENTS
See A056371 for an explanation of step shifts. 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]
PROG
(PARI) \\ see A056391 for Polya enumeration functions
a(n) = NonequivalentStructs(StepShiftPerms(n), n); \\ Andrew Howroyd, Oct 14 2017
CROSSREFS
Row sums of A288620.
Sequence in context: A319417 A056394 A056395 * A053031 A018674 A076518
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Jun 11 2017
STATUS
approved