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 A056375 Number of step shifted (decimated) sequences using a maximum of six different symbols. 8
 6, 36, 126, 756, 2016, 23976, 46956, 435456, 1683576, 15128856, 36284472, 547204896, 1088416056, 13060989936, 58782164616, 352913845536, 1057916846196, 16926689693376, 33853322280036, 457078896068256, 1828085963706576 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS See A056371 for an explanation of step shifts. 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 G. C. Greubel, Table of n, a(n) for n = 1..1275 R. C. Titsworth, Equivalence classes of periodic sequences, Illinois J. Math., 8 (1964), 266-270. FORMULA 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 MATHEMATICA a[m_, n_] := (1/EulerPhi[n])*Sum[If[GCD[k, n] == 1, m^DivisorSum[n, EulerPhi[#]/MultiplicativeOrder[k, #] &], 0], {k, 1, n}]; Table[a[6, n], {n, 1, 21}] (* Jean-François Alcover, Dec 04 2015 *) CROSSREFS Cf. A056414. A row or column of A132191. Sequence in context: A264366 A061707 A253945 * A321579 A018214 A181478 Adjacent sequences:  A056372 A056373 A056374 * A056376 A056377 A056378 KEYWORD nonn AUTHOR EXTENSIONS More terms from Max Alekseyev, Nov 08 2007 STATUS approved

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Last modified January 20 17:05 EST 2019. Contains 319335 sequences. (Running on oeis4.)