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A056374
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Number of step shifted (decimated) sequences using a maximum of five different symbols.
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6
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5, 25, 75, 375, 825, 8125, 13175, 103125, 327125, 2445625, 4884435, 61640625, 101732425, 1017323125, 3816215625, 19104609375, 47683838325, 635787765625, 1059638680675, 11924780390625, 39736963221875, 238418603522125, 541860418146375
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OFFSET
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1,1
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COMMENTS
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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. [See A056391 for pdf file of Chap. 2]
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LINKS
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G. C. Greubel, Table of n, a(n) for n = 1..1000
R. C. Titsworth, Equivalence classes of periodic sequences, Illinois J. Math., 8 (1964), 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, Nov 08 2007
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MATHEMATICA
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a[m_, n_] := (1/EulerPhi[n])*Sum[If[GCD[k, n] == 1, m^DivisorSum[n, EulerPhi[#]/MultiplicativeOrder[k, #] &], 0], {k, 1, n}]; Table[a[5, n], {n, 1, 23}] (* Jean-François Alcover, Dec 04 2015 *)
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CROSSREFS
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Cf. A056413.
A row or column of A132191.
Sequence in context: A154286 A331575 A078234 * A301912 A171272 A243303
Adjacent sequences: A056371 A056372 A056373 * A056375 A056376 A056377
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KEYWORD
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nonn
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AUTHOR
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Marks R. Nester
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EXTENSIONS
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More terms from Max Alekseyev, Nov 08 2007
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STATUS
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approved
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