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Search: id:A056372
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| A056372 |
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Number of step shifted (decimated) sequences using a maximum of three different symbols. |
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+0
11
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| 3, 9, 18, 54, 72, 405, 390, 1944, 3411, 14985, 17802, 139968, 133104, 798525, 1804518, 5454378, 8072532, 64599849, 64573626, 437732424, 872157294, 3138159429, 4279259574, 35362084140, 42364514403, 211822562025, 423646166250
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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See A056371 for an explanation of step shifts.
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REFERENCES
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M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia.
R. C. Titsworth, (1964). Equivalence classes of periodic sequences. Illinois J. Math. 8: 266-270.
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FORMULA
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The cycle index is implicit in Titsworth.
Sequences A056372-A056375 fit a general formula, implemented in PARI/GP as follows: { a(m,n) = sum(k=1, n, if(gcd(k, n)==1, m^sumdiv(n, d, eulerphi(d)/znorder(Mod(k, d))), 0); ) / eulerphi(n) }. - Max Alekseyev (maxal(AT)cs.ucsd.edu), Nov 08 2007
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CROSSREFS
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Cf. A056411.
A row or column of A132191.
Sequence in context: A062882 A027101 A015656 this_sequence A101652 A026565 A133136
Adjacent sequences: A056369 A056370 A056371 this_sequence A056373 A056374 A056375
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KEYWORD
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nonn
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AUTHOR
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Marks R. Nester (nesterm(AT)dpi.qld.gov.au)
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EXTENSIONS
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More terms from Max Alekseyev (maxal(AT)cs.ucsd.edu), Nov 08 2007
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