A060014 Sum of orders of all permutations of n letters.

1, 1, 3, 13, 67, 471, 3271, 31333, 299223, 3291487, 39020911, 543960561, 7466726983, 118551513523, 1917378505407, 32405299019941, 608246253790591, 12219834139189263, 253767339725277823, 5591088918313739017, 126036990829657056711, 2956563745611392385211

Offset

0,3

Comments

Conjecture: This sequence eventually becomes cyclic mod n for all n. - Isaac Saffold, Dec 01 2019

References

D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, Section XIII.2, p. 460.

Links

Alois P. Heinz, Table of n, a(n) for n = 0..170

FindStat - Combinatorial Statistic Finder, The order of a permutation

Joshua Harrington, Lenny Jones, and Alicia Lamarche, Characterizing Finite Groups Using the Sum of the Orders of the Elements, International Journal of Combinatorics, Volume 2014, Article ID 835125, 8 pages.

Formula

E.g.f.: Sum_{n>0} (n*Sum_{i|n} (moebius(n/i)*Product_{j|i} exp(x^j/j))). - Vladeta Jovovic, Dec 29 2004; The sum over n should run to at least A000793(k) for producing the k-th entry. - Wouter Meeussen, Jun 16 2012

a(n) = Sum_{k>=1} k* A057731(n,k). - R. J. Mathar, Aug 31 2017

Example

For n = 4 there is 1 permutation of order 1, 9 permutations of order 2, 8 of order 3 and 6 of order 4, for a total of 67.

Maple

b:= proc(n, g) option remember; `if`(n=0, g, add((j-1)!
      *b(n-j, ilcm(g, j))*binomial(n-1, j-1), j=1..n))
    end:
a:= n-> b(n, 1):
seq(a(n), n=0..30);  # Alois P. Heinz, Jul 11 2017

Mathematica

CoefficientList[Series[Sum[n Fold[#1+MoebiusMu[n/#2] Apply[Times, Exp[x^#/#]&/@Divisors[#2] ]&, 0, Divisors[n]], {n, Max[Apply[LCM, Partitions[19], 1]]}], {x, 0, 19}], x] Range[0, 19]! (* Wouter Meeussen, Jun 16 2012 *)
a[ n_] := If[ n < 1, Boole[n == 0], 1 + Total @ Apply[LCM, Map[Length, First /@ PermutationCycles /@ Drop[Permutations @ Range @ n, 1], {2}], 1]]; (* Michael Somos, Aug 19 2018 *)

Prog

(PARI) \\ Naive method -- sum over cycles directly
cycleDecomposition(v:vec)={
    my(cyc=List(), flag=#v+1, n);
    while((n=vecmin(v))<#v,
        my(cur=List(), i, tmp);
        while(v[i++]!=n, );
        while(v[i] != flag,
            listput(cur, tmp=v[i]);
            v[i]=flag;
            i=tmp
        );
        if(#cur>1, listput(cyc, Vec(cur)))    \\ Omit length-1 cycles
    );
    Vec(cyc)
};
permutationOrder(v:vec)={
    lcm(apply(length, cycleDecomposition(v)))
};
a(n)=sum(i=0, n!-1, permutationOrder(numtoperm(n, i)))
\\ Charles R Greathouse IV, Nov 06 2014
(PARI)
A060014(n) =
{
  my(factn = n!, part, nb, i, j, res = 0);
  forpart(part = n,
    nb = 1; j = 1;
    for(i = 1, #part,
      if (i == #part || part[i + 1] != part[i],
        nb *= (i + 1 - j)! * part[i]^(i + 1 - j);
        j = i + 1));
    res += (factn / nb) * lcm(Vec(part)));
  res;
} \\ Jerome Raulin, Jul 11 2017 (much faster, O(A000041(n)) vs O(n!))

Crossrefs

Cf. A000793, A028418, A060015, A057731, A074859, A290932.

Sequence in context: A080832 A194019 A020017 * A182666 A042659 A054132

Adjacent sequences: A060011 A060012 A060013 * A060015 A060016 A060017

Keyword

nonn,nice,easy

Author

N. J. A. Sloane, Mar 17 2001

Extensions

More terms from Vladeta Jovovic, Mar 18 2001

More terms from Alois P. Heinz, Feb 14 2013

Status

approved