OFFSET
1,1
COMMENTS
See A056371 for an explanation of step shifts.
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..2000
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[3, n], {n, 1, 27}] (* Jean-François Alcover, Dec 04 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Max Alekseyev, Nov 08 2007
STATUS
approved