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A060222
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Number of orbits of length n under the full 19-shift (whose periodic points are counted by A001029).
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2
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19, 171, 2280, 32490, 495216, 7839780, 127695960, 2122929090, 35854187880, 613106378136, 10590023536200, 184442905990860, 3234844881712080, 57071906063500860, 1012075135324821024, 18027588346914850290, 322375697516753069760, 5784852794310472599780, 104127350297911241532840
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OFFSET
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1,1
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COMMENTS
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Number of monic irreducible polynomials of degree n over GF(19). - Andrew Howroyd, Dec 10 2017
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LINKS
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FORMULA
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a(n) = (1/n)* Sum_{d|n} mu(d)*A001029(n/d).
G.f.: Sum_{k>=1} mu(k)*log(1/(1 - 19*x^k))/k. - Ilya Gutkovskiy, May 20 2019
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EXAMPLE
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a(2)=171 since there are 361 points of period 2 in the full 19-shift and 19 fixed points, so there must be (361-19)/2 = 171 orbits of length 2.
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MATHEMATICA
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a[n_]:=(1/n) Sum[MoebiusMu[d] 19^(n/d), {d, Divisors[n]}]; Table[a[n], {n, 20}] (* Vincenzo Librandi, Sep 19 2017 *)
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PROG
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(PARI) a001029(n) = 19^n;
a(n) = (1/n)*sumdiv(n, d, moebius(d)*a001029(n/d)); \\ Michel Marcus, Sep 11 2017
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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