cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A060217 Number of orbits of length n under the full 14-shift (whose periodic points are counted by A001023).

Original entry on oeis.org

14, 91, 910, 9555, 107562, 1254435, 15059070, 184468830, 2295671560, 28925411697, 368142288150, 4724492067295, 61054982558010, 793714765724595, 10371206370484778, 136122083520848880, 1793608631137129170, 23715491899442676060, 314542313628890231430, 4183412771249777343369
Offset: 1

Views

Author

Thomas Ward, Mar 21 2001

Keywords

Comments

Number of Lyndon words (aperiodic necklaces) with n beads of 14 colors. - Andrew Howroyd, Dec 10 2017

Examples

			a(2)=91 since there are 196 points of period 2 in the full 14-shift and 14 fixed points, so there must be (196-14)/2 = 91 orbits of length 2.
		

Crossrefs

Column 14 of A074650.
Cf. A001023.

Programs

  • Magma
    A060217:= func< n | (&+[MoebiusMu(d)*14^Floor(n/d): d in Divisors(n)])/n >;
    [A060217(n): n in [1..40]]; // G. C. Greubel, Aug 01 2024
    
  • Mathematica
    A060217[n_]:= DivisorSum[n, MoebiusMu[#]*14^(n/#) &]/n;
    Table[A060217[n], {n,40}] (* G. C. Greubel, Aug 01 2024 *)
  • PARI
    a001023(n) = 14^n;
    a(n) = (1/n)*sumdiv(n, d, moebius(d)*a001023(n/d)); \\ Michel Marcus, Sep 11 2017
    
  • SageMath
    def A060217(n): return sum(moebius(k)*14^(n//k) for k in (1..n) if (k).divides(n))/n
    [A060217(n) for n in range(1,41)] # G. C. Greubel, Aug 01 2024

Formula

a(n) = (1/n)* Sum_{d|n} mu(d)*A001023(n/d).
G.f.: Sum_{k>=1} mu(k)*log(1/(1 - 14*x^k))/k. - Ilya Gutkovskiy, May 19 2019

Extensions

More terms from Michel Marcus, Sep 11 2017