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A056431 Step cyclic shifted sequence structures using a maximum of four different symbols. +0
4
1, 2, 3, 7, 7, 33, 29, 149, 245, 1230, 1665, 15973, 18199, 134482, 376433, 1415209, 2634597, 26534612, 33499359, 287002711, 727425501, 3332040944, 5794658931, 61120855045, 93825569009, 601444738252 (list; graph; listen)
OFFSET

1,2

COMMENT

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.

FORMULA

Use de Bruijn's generalization of Polya's enumeration theorem as discussed in reference.

CROSSREFS

Cf. A056412.

Sequence in context: A104138 A083809 A092967 this_sequence A011027 A100072 A089008

Adjacent sequences: A056428 A056429 A056430 this_sequence A056432 A056433 A056434

KEYWORD

nonn

AUTHOR

Marks R. Nester (nesterm(AT)dpi.qld.gov.au)

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Last modified December 16 13:01 EST 2009. Contains 170825 sequences.


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