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.

Showing 1-9 of 9 results.

A074103 a(n) = n!/A074859(n).

Original entry on oeis.org

1, 1, 2, 3, 4, 6, 3, 12, 15, 20, 30, 15, 60, 60, 84, 105, 140, 210, 105, 420, 420, 420, 315, 840, 840, 1260, 1260, 1540, 2310, 2520, 4620, 4620, 5460, 5460, 9240, 9240, 13860, 13860, 16380, 16380, 27720, 30030, 32760, 60060, 60060, 60060, 45045, 120120
Offset: 0

Views

Author

Vladeta Jovovic, Sep 15 2002

Keywords

Comments

1/a(n) is probability that a random degree-n permutation has the maximum possible order.

Crossrefs

Programs

  • Mathematica
    g[n_] := g[n] = Max[LCM @@@ IntegerPartitions[n]];
    f[x_, n_] := Total[(MoebiusMu[g[n]/#]*Exp[Total[(x^#/#&) /@ Divisors[#]]]&) /@ Divisors[g[n]]];
    a[0] = 1; a[n_] := 1/SeriesCoefficient[f[x, n], {x, 0, n}];
    Table[a[n], {n, 0, 50}] (* Jean-François Alcover, May 24 2019 *)

Extensions

More terms from Max Alekseyev, Jun 13 2011

A000793 Landau's function g(n): largest order of permutation of n elements. Equivalently, largest LCM of partitions of n.

Original entry on oeis.org

1, 1, 2, 3, 4, 6, 6, 12, 15, 20, 30, 30, 60, 60, 84, 105, 140, 210, 210, 420, 420, 420, 420, 840, 840, 1260, 1260, 1540, 2310, 2520, 4620, 4620, 5460, 5460, 9240, 9240, 13860, 13860, 16380, 16380, 27720, 30030, 32760, 60060, 60060, 60060, 60060, 120120
Offset: 0

Views

Author

Keywords

Comments

Also the largest orbit size (cycle length) for the permutation A057511 acting on Catalan objects (e.g., planar rooted trees, parenthesizations). - Antti Karttunen, Sep 07 2000
Grantham mentions that he computed a(n) for n <= 500000.
An easy lower bound is a(n) >= A002110(max{ m | A007504(m) <= n}), with strict inequality if n is not in A007504 (sum of the first m primes). Indeed, if A007504(m) <= n, the partition of n into the first m primes and maybe one additional term will have an LCM greater than or equal to primorial(m). If n > A007504(m) then a(n) >= (3/2)*A002110(m) by replacing the initial 2 by 3. But even for n = A007504(m), one has a(n) > A002110(m) for m > 8, since replacing 2+23 in 2+3+5+7+11+13+17+19+23 by 16+9, one has an LCM of 8*3*primorial(8) > primorial(9) because 24 > 23. - M. F. Hasler, Mar 29 2015
Maximum degree of the splitting field of a polynomial of degree n over a finite field, since over a finite field the degree of the splitting field is the least common multiple of the degrees of the irreducible polynomial factors of the polynomial. - Charles R Greathouse IV, Apr 27 2015
Maximum order of the elements in the symmetric group S_n. - Jianing Song, Dec 12 2021

Examples

			G.f. = 1 + x + 2*x^2 + 3*x^3 + 4*x^4 + 6*x^5 + 6*x^6 + 12*x^7 + 15*x^8 + ...
From _Joerg Arndt_, Feb 15 2013: (Start)
The 15 partitions of 7 are the following:
[ #]  [ partition ]   lcm( parts )
[ 1]  [ 1 1 1 1 1 1 1 ]   1
[ 2]  [ 1 1 1 1 1 2 ]   2
[ 3]  [ 1 1 1 1 3 ]   3
[ 4]  [ 1 1 1 2 2 ]   2
[ 5]  [ 1 1 1 4 ]   4
[ 6]  [ 1 1 2 3 ]   6
[ 7]  [ 1 1 5 ]   5
[ 8]  [ 1 2 2 2 ]   2
[ 9]  [ 1 2 4 ]   4
[10]  [ 1 3 3 ]   3
[11]  [ 1 6 ]   6
[12]  [ 2 2 3 ]   6
[13]  [ 2 5 ]  10
[14]  [ 3 4 ]  12  (max)
[15]  [ 7 ]   7
The maximum (LCM) value attained is 12, so a(7) = 12.
(End)
		

References

  • J. Haack, "The Mathematics of Steve Reich's Clapping Music," in Bridges: Mathematical Connections in Art, Music and Science: Conference Proceedings, 1998, Reza Sarhangi (ed.), 87-92.
  • Edmund Georg Hermann Landau, Handbuch der Lehre von der Verteilung der Primzahlen, Chelsea Publishing, NY 1953, p. 223.
  • J.-L. Nicolas, On Landau's function g(n), pp. 228-240 of R. L. Graham et al., eds., Mathematics of Paul Erdős I.
  • S. M. Shah, An inequality for the arithmetical function g(x), J. Indian Math. Soc., 3 (1939), 316-318. [See below for a scan of the first page.]
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Haskell
    a000793 = maximum . map (foldl lcm 1) . partitions where
       partitions n = ps 1 n where
          ps x 0 = [[]]
          ps x y = [t:ts | t <- [x..y], ts <- ps t (y - t)]
    -- Reinhard Zumkeller, Mar 29 2015
    
  • Maple
    A000793 := proc(n)
        l := 1:
        p := combinat[partition](n):
        for i from 1 to combinat[numbpart](n) do
            if ilcm( p[i][j] $ j=1..nops(p[i])) > l then
                l := ilcm( p[i][j] $ j=1..nops(p[i]))
            end if:
        end do:
        l ;
    end proc:
    seq(A000793(n),n=0..30) ; # James Sellers, Dec 07 2000
    seq( max( op( map( x->ilcm(op(x)), combinat[partition](n)))), n=0..30); # David Radcliffe, Feb 28 2006
    # third Maple program:
    b:= proc(n, i) option remember; local p;
          p:= `if`(i<1, 1, ithprime(i));
          `if`(n=0 or i<1, 1, max(b(n, i-1),
               seq(p^j*b(n-p^j, i-1), j=1..ilog[p](n))))
        end:
    a:=n->b(n, `if`(n<8, 3, numtheory[pi](ceil(1.328*isqrt(n*ilog(n)))))):
    seq(a(n), n=0..60);  # Alois P. Heinz, Feb 16 2013
  • Mathematica
    f[n_] := Max@ Apply[LCM, IntegerPartitions@ n, 1]; Array[f, 47] (* Robert G. Wilson v, Oct 23 2011 *)
    b[n_, i_] := b[n, i] = Module[{p}, p = If[i<1, 1, Prime[i]]; If[n == 0 || i<1, 1, Max[b[n, i-1], Table[p^j*b[n-p^j, i-1], {j, 1, Log[p, n] // Floor}]]]]; a[n_] := b[n, If[n<8, 3, PrimePi[Ceiling[1.328*Sqrt[n*Log[n] // Floor]]]]]; Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Mar 07 2014, after Alois P. Heinz *)
  • PARI
    {a(n) = my(m, t, j, u); if( n<2, n>=0, m = ceil(n / exp(1)); t = ceil( (n/m)^m ); j=1; for( i=2, t, u = factor(i); u = sum( k=1, matsize(u)[1], u[k,1]^u[k,2]); if( u<=n, j=i)); j)}; /* Michael Somos, Oct 20 2004 */
    
  • PARI
    c=0;A793=apply(t->eval(concat(Vec(t)[#Str(c++) .. -1])),select(t->#t,readstr("/tmp/b000793.txt")));A000793(n)=A793[n+1] \\ Assumes the b-file in the /tmp (or C:\tmp) folder. - M. F. Hasler, Mar 29 2015
    
  • PARI
    A008475(n)=my(f=factor(n)); sum(i=1,#f~,f[i,1]^f[i,2]);
    a(n)=
    {
      if(n<2, return(1));
      forstep(i=ceil(exp(1.05315*sqrt(log(n)*n))), 2, -1,
        if(A008475(i)<=n, return(i))
      );
      1;
    } \\ Charles R Greathouse IV, Apr 28 2015
    
  • PARI
    { \\ translated from code given by Tomas Rokicki
      my( N = 100 );
      my( V = vector(N,j,1) );
       forprime (i=2, N,  \\ primes i
          forstep (j=N, i,  -1,
             my( hi = V[j] );
             my( pp = i );  \\ powers of prime i
             while ( pp<=j,  \\ V[] is 1-based
                 hi = max(if(j==pp, pp, V[j-pp]*pp), hi);
                 pp *= i;
             );
             V[j] = hi;
          );
       );
       print( V );  \\ all values
    \\   print( V[N] );  \\ just a(N)
    \\  print("0 1");  for (n=1, N, print(n, " ", V[n]) );  \\ b-file
    } \\ Joerg Arndt, Nov 14 2016
    
  • PARI
    {a(n) = my(m=1); if( n<0, 0, forpart(v=n, m = max(m, lcm(Vec(v)))); m)}; /* Michael Somos, Sep 04 2017 */
    
  • Python
    from sympy import primerange
    def aupton(N): # compute terms a(0)..a(N)
        V = [1 for j in range(N+1)]
        for i in primerange(2, N+1):
            for j in range(N, i-1, -1):
                hi = V[j]
                pp = i
                while pp <= j:
                    hi = max((pp if j==pp else V[j-pp]*pp), hi)
                    pp *= i
                V[j] = hi
        return V
    print(aupton(47)) # Michael S. Branicky, Oct 09 2022 after Joerg Arndt
    
  • Python
    from sympy import primerange,sqrt,log,Rational
    def f(N): # compute terms a(0)..a(N)
        V = [1 for j in range(N+1)]
        if N < 4:
            C = 2
        else:
            C = Rational(166,125)
        for i in primerange(C*sqrt(N*log(N))):
            for j in range(N, i-1, -1):
                hi = V[j]
                pp = i
                while pp <= j:
                    hi = max(V[j-pp]*pp, hi)
                    pp *= i
                V[j] = hi
        return V
    # Philip Turecek, Mar 31 2023
    
  • Sage
    def a(n):
      return max([lcm(l) for l in Partitions(n)])
    # Philip Turecek, Mar 28 2023
  • Scheme
    ;; A naive algorithm searching through all partitions of n:
    (define (A000793 n) (let ((maxlcm (list 0))) (fold_over_partitions_of n 1 lcm (lambda (p) (set-car! maxlcm (max (car maxlcm) p)))) (car maxlcm)))
    (define (fold_over_partitions_of m initval addpartfun colfun) (let recurse ((m m) (b m) (n 0) (partition initval)) (cond ((zero? m) (colfun partition)) (else (let loop ((i 1)) (recurse (- m i) i (+ 1 n) (addpartfun i partition)) (if (< i (min b m)) (loop (+ 1 i))))))))
    ;; From Antti Karttunen, May 17 2013.
    

Formula

Landau: lim_{n->oo} (log a(n)) / sqrt(n log n) = 1.
For bounds, see the Shah and Massias references.
For n >= 2, a(n) = max_{k} A008475(k) <= n. - Joerg Arndt, Nov 13 2016

Extensions

More terms from David W. Wilson
Removed erroneous comment about a(16) which probably originated from misreading a(15)=105 as a(16) because of offset=0: a(16) = 4*5*7 = 140 is correct as it stands. - M. F. Hasler, Feb 02 2009

A057731 Irregular triangle read by rows: T(n,k) = number of elements of order k in symmetric group S_n, for n >= 1, 1 <= k <= g(n), where g(n) = A000793(n) is Landau's function.

Original entry on oeis.org

1, 1, 1, 1, 3, 2, 1, 9, 8, 6, 1, 25, 20, 30, 24, 20, 1, 75, 80, 180, 144, 240, 1, 231, 350, 840, 504, 1470, 720, 0, 0, 504, 0, 420, 1, 763, 1232, 5460, 1344, 10640, 5760, 5040, 0, 4032, 0, 3360, 0, 0, 2688, 1, 2619, 5768, 30996, 3024, 83160, 25920, 45360, 40320, 27216, 0, 30240, 0, 25920, 24192, 0, 0, 0, 0, 18144
Offset: 1

Views

Author

Roger Cuculière, Oct 29 2000

Keywords

Comments

Every row for n >= 7 contains zeros. Landau's function quickly becomes > 2*n, and there is always a prime between n and 2*n. T(n,p) = 0 for such a prime p. - Franklin T. Adams-Watters, Oct 25 2011

Examples

			Triangle begins:
  1;
  1,   1;
  1,   3,   2;
  1,   9,   8,   6;
  1,  25,  20,  30,  24,   20;
  1,  75,  80, 180, 144,  240;
  1, 231, 350, 840, 504, 1470, 720, 0, 0, 504, 0, 420;
  ...
		

References

  • Herbert S. Wilf, "The asymptotics of e^P(z) and the number of elements of each order in S_n." Bull. Amer. Math. Soc., 15.2 (1986), 225-232.

Crossrefs

Cf. A000793, also A054522 (for cyclic group), A057740 (alternating group), A057741 (dihedral group).
Rows sums give A000142, last elements of rows give A074859, columns k=2, 3, 5, 7, 11 give A001189, A001471, A059593, A153760, A153761. - Alois P. Heinz, Feb 16 2013
Main diagonal gives A074351.
Cf. A222029.

Programs

  • Magma
    {* Order(g) : g in Sym(6) *};
    
  • Maple
    with(group):
    for n from 1 do
        f := [seq(0,i=1..n!)] ;
        mknown := 0 ;
        # loop through the permutations of n
        Sn := combinat[permute](n) ;
        for per in Sn do
            # write this permutation in cycle notation
            gen := convert(per,disjcyc) ;
            # compute the list of lengths of the cycles, then the lcm of these
            cty := [seq(nops(op(i,gen)),i=1..nops(gen))] ;
            if cty <> [] then
                lcty := lcm(op(cty)) ;
            else
                lcty := 1 ;
            end if;
            f := subsop(lcty = op(lcty,f)+1,f) ;
            mknown := max(mknown,lcty) ;
        end do:
        ff := add(el,el=f) ;
        print(seq(f[i],i=1..mknown)) ;
    end do: # R. J. Mathar, May 26 2014
    # second Maple program:
    b:= proc(n, g) option remember; `if`(n=0, x^g, add((j-1)!
          *b(n-j, ilcm(g, j))*binomial(n-1, j-1), j=1..n))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=1..degree(p)))(b(n, 1)):
    seq(T(n), n=1..12);  # Alois P. Heinz, Jul 11 2017
  • Mathematica
    <Jean-François Alcover, Aug 31 2016 *)
    b[n_, g_] := b[n, g] = If[n == 0, x^g, Sum[(j-1)!*b[n-j, LCM[g, j]]* Binomial[n-1, j-1], {j, 1, n}]];
    T[n_] := Function[p, Table[Coefficient[p, x, i], {i, 1, Exponent[p, x]}]][ b[n, 1]];
    Array[T, 12] // Flatten (* Jean-François Alcover, May 03 2019, after Alois P. Heinz *)
  • PARI
    T(n,k)={n!*polcoeff(sumdiv(k, i, moebius(k/i)*exp(sumdiv(i, j, x^j/j) + O(x*x^n))), n)} \\ Andrew Howroyd, Jul 02 2018

Formula

Sum_{k=1..A000793(n)} k*T(n,k) = A060014(n); A000793 = Landau's function.

Extensions

More terms from N. J. A. Sloane, Nov 01 2000

A060014 Sum of orders of all permutations of n letters.

Original entry on oeis.org

1, 1, 3, 13, 67, 471, 3271, 31333, 299223, 3291487, 39020911, 543960561, 7466726983, 118551513523, 1917378505407, 32405299019941, 608246253790591, 12219834139189263, 253767339725277823, 5591088918313739017, 126036990829657056711, 2956563745611392385211
Offset: 0

Views

Author

N. J. A. Sloane, Mar 17 2001

Keywords

Comments

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

Examples

			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.
		

References

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

Crossrefs

Programs

  • 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 *)
  • 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!))

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

Extensions

More terms from Vladeta Jovovic, Mar 18 2001
More terms from Alois P. Heinz, Feb 14 2013

A074064 Number of cycle types of degree-n permutations having the maximum possible order.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 4, 1, 1, 1, 1, 2, 3, 1, 1, 2, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 1, 1, 2, 4, 1, 1, 1, 1, 2, 3, 1, 1, 2, 3, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 2, 4
Offset: 0

Views

Author

Vladeta Jovovic, Sep 15 2002

Keywords

Examples

			For n = 22 we have 4 such cycle types: [1, 1, 1, 3, 4, 5, 7], [1, 2, 3, 4, 5, 7], [3, 3, 4, 5, 7], [4, 5, 6, 7].
		

Crossrefs

Programs

  • Maple
    A000793 := proc(n) option remember; local l,p,i ; l := 1: p := combinat[partition](n): for i from 1 to combinat[numbpart](n) do if ilcm( p[i][j] $ j=1..nops(p[i])) > l then l := ilcm( p[i][j] $ j=1..nops(p[i])) ; fi: od: RETURN(l) ; end proc:
    taylInv := proc(i,n) local resul,j,idiv,k ; resul := 1 ; idiv := numtheory[divisors](i) ; for k from 1 to nops(idiv) do j := op(k,idiv) ; resul := resul*taylor(1/(1-x^j),x=0,n+1) ; resul := convert(taylor(resul,x=0,n+1),polynom) ; od ; coeftayl(resul,x=0,n) ; end proc:
    A074064 := proc(n) local resul,a793,dvs,i,k ; resul := 0: a793 := A000793(n) ; dvs := numtheory[divisors](a793) ; for k from 1 to nops(dvs) do i := op(k,dvs) ; resul := resul+numtheory[mobius](a793/i)*taylInv(i,n) ; od : RETURN(resul) ; end proc: # R. J. Mathar, Mar 30 2007
  • Mathematica
    b[n_, i_] := b[n, i] = Module[{p}, p = If[i < 1, 1, Prime[i]]; If[n == 0 || i < 1, 1, Max[b[n, i-1], Table[p^j*b[n-p^j, i-1], {j, 1, Log[p, n] // Floor}]]]];
    g[n_] := g[n] = b[n, If[n < 8, 3, PrimePi[Ceiling[1.328*Sqrt[n*Log[n] // Floor]]]]];
    a[n_] := a[n] = SeriesCoefficient[Sum[MoebiusMu[g[n]/i]/Product[1-x^j, {j, Divisors[i]}], {i, Divisors[g[n]]}] + O[x]^(n+1), n];
    Table[Print["a(", n, ") = ", a[n]]; a[n], {n, 0, 100}] (* Jean-François Alcover, Apr 25 2017, after Alois P. Heinz *)

Formula

Coefficient of x^n in expansion of Sum_{i divides A000793(n)} mu(A000793(n)/i)*1/Product_{j divides i} (1-x^j).

Extensions

More terms from R. J. Mathar, Mar 30 2007
More terms from Sean A. Irvine, Oct 04 2011
More terms from Alois P. Heinz, Mar 29 2015

A074351 Number of elements of S_n having order n.

Original entry on oeis.org

1, 1, 2, 6, 24, 240, 720, 5040, 40320, 514080, 3628800, 80166240, 479001600, 6797831040, 93774320640, 1307674368000, 20922789888000, 523845011289600, 6402373705728000, 153101632051630080, 2471368711740364800, 51182316789956352000, 1124000727777607680000
Offset: 1

Views

Author

K Murray Peebles (m.peebles(AT)sms.ed.ac.uk), Sep 26 2002

Keywords

Comments

If n is a prime power then a(n) = (n-1)!. - Vladeta Jovovic, Sep 29 2002

Examples

			a(10) = 514080 because {10}, {5, 2, 2, 1} and {5, 2, 1, 1, 1} are the unique multisets of cycle lengths summing to 10 whose lcm is 10 and 10!/(1!*10^1) + 10!/(1!*2!*1!*5^1*2^2*1^1) + 10!/(1!*1!*3!*5^1*2^1*1^3) = 514080.
		

Crossrefs

Cf. A001189, A074859, A290961 (the same for endofunctions).
Main diagonal of A057731.

Programs

  • Mathematica
    a[n_] := SeriesCoefficient[ Series[ Sum[ MoebiusMu[n/i]*Exp[Sum[x^j/j, {j, Divisors[i]}]], {i, Divisors[n]}], {x, 0, n}], n]*n!; Table[a[n], {n, 1, 21}] (* Jean-François Alcover, May 21 2012, after Vladeta Jovovic *)
  • PARI
    a(n)={n!*polcoeff(sumdiv(n, i, moebius(n/i)*exp(sumdiv(i, j, x^j/j) + O(x*x^n))), n)} \\ Andrew Howroyd, Jul 02 2018

Formula

n!/(a_1!*a_2!*...*a_d!*k_1^a_1*k_2^a_2*...*k_d^a_d) is the number of elements of S_n having order n that are permutations with distinct cycle-lengths k_1, ..., k_d having multiplicities a_1, ..., a_d, where lcm(k_1, ..., k_d)=n. Summing over all permutation types gives the total.
a(n) = n!*coefficient of x^n in expansion of Sum_{i divides n} mu(n/i)*exp(Sum_{j divides i} x^j/j). - Vladeta Jovovic, Sep 29 2002

A074115 a(n) = n!/A000793(n).

Original entry on oeis.org

1, 1, 1, 2, 6, 20, 120, 420, 2688, 18144, 120960, 1330560, 7983360, 103783680, 1037836800, 12454041600, 149448499200, 1693749657600, 30487493836800, 289631191449600, 5792623828992000, 121645100408832000, 2676192208994304000, 30776210403434496000
Offset: 0

Views

Author

Vladeta Jovovic, Sep 16 2002

Keywords

Crossrefs

Cf. A074859.

Extensions

a(0)=1 prepended by Alois P. Heinz, Jul 12 2017

A162682 If S is countable finite set, we can define n as number of elements in S. There are n^n distinct functions f(S)->S. Each function has a fixed point, or an orbit in S. This sequence is a number of distinct functions g(S)->S, with largest orbit.

Original entry on oeis.org

1, 1, 1, 2, 6, 20, 840, 420, 2688, 18144, 120960, 15966720, 7983360, 1349187840, 1037836800, 12454041600, 149448499200, 1693749657600, 579262382899200, 289631191449600, 115852476579840000, 26822744640147456000, 4750241170964889600000, 30776210403434496000
Offset: 0

Views

Author

Dmitriy Samsonov (dmitriy.samsonov(AT)gmail.com), Jul 10 2009

Keywords

Comments

Sizes of orbits are given by A000793.

Examples

			For S={a}, n=1 and only one operation possible {a->a}. For S={a,b}, n=2 and possible operations are {a->a,b->a}, {a->a,b->b}, {a->b,b->a},{a->b,b->b}. Longest orbit generated by applying operation {a->b,b->a}: initial set (a,b), applying function gives orbit - (b,a), (a,b). All other possible functions are generating fixed points.
		

Crossrefs

Formula

a(n) = A222029(n,A000793(n)). - Alois P. Heinz, Aug 14 2017

Extensions

a(0), a(10)-a(23) from Alois P. Heinz, Jul 12 2017
a(21)-a(22) corrected by Alois P. Heinz, Aug 16 2017

A074260 Number of labeled cyclic subgroups of S_n having the maximum possible order.

Original entry on oeis.org

1, 1, 1, 1, 3, 10, 120, 105, 336, 2268, 15120, 332640, 498960, 6486480, 43243200, 259459200, 3113510400, 35286451200, 1270312243200, 3016991577600, 60339831552000, 1267136462592000, 37169336236032000, 160292762517888000
Offset: 0

Views

Author

Vladeta Jovovic, Sep 20 2002

Keywords

Crossrefs

Formula

a(n) = A074859(n)/A000010(A000793(n)).
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