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.

A074761 Number of partitions of n of order n.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 1, 9, 1, 4, 5, 1, 1, 12, 1, 27, 7, 6, 1, 81, 1, 7, 1, 54, 1, 407, 1, 1, 11, 9, 13, 494, 1, 10, 13, 423, 1, 981, 1, 137, 115, 12, 1, 1309, 1, 59, 17, 193, 1, 240, 21, 1207, 19, 15, 1, 47274, 1, 16, 239, 1, 25, 3284, 1, 333, 23, 3731, 1, 42109, 1, 19
Offset: 1

Views

Author

Vladeta Jovovic, Sep 28 2002

Keywords

Comments

Order of partition is lcm of its parts.
a(n) is the number of conjugacy classes of the symmetric group S_n such that a representative of the class has order n. Here order means the order of an element of a group. Note that a(n) = 1 if and only if n is a prime power. - W. Edwin Clark, Aug 05 2014

Examples

			The a(15) = 5 partitions are (15), (5,3,3,3,1), (5,5,3,1,1), (5,3,3,1,1,1,1), (5,3,1,1,1,1,1,1,1). - _Gus Wiseman_, Aug 01 2018
		

Crossrefs

Programs

  • Maple
    A:= proc(n)
          uses numtheory;
          local S;
        S:= add(mobius(n/i)*1/mul(1-x^j,j=divisors(i)),i=divisors(n));
        coeff(series(S,x,n+1),x,n);
    end proc:
    seq(A(n),n=1..100); # Robert Israel, Aug 06 2014
  • Mathematica
    a[n_] := With[{s = Sum[MoebiusMu[n/i]*1/Product[1-x^j, {j, Divisors[i]}], {i, Divisors[n]}]}, SeriesCoefficient[s, {x, 0, n}]]; Array[a, 80] (* Jean-François Alcover, Feb 29 2016 *)
    Table[Length[Select[IntegerPartitions[n],LCM@@#==n&]],{n,50}] (* Gus Wiseman, Aug 01 2018 *)
  • PARI
    pr(k, x)={my(t=1); fordiv(k, d, t *= (1-x^d) ); return(t); }
    a(n) =
    {
        my( x = 'x+O('x^(n+1)) );
        polcoeff( Pol( sumdiv(n, i, moebius(n/i) / pr(i, x) ) ), n );
    }
    vector(66, n, a(n) )
    \\ Joerg Arndt, Aug 06 2014

Formula

Coefficient of x^n in expansion of Sum_{i divides n} A008683(n/i)*1/Product_{j divides i} (1-x^j).

A168532 Triangle read by rows, A054525 * A168021.

Original entry on oeis.org

1, 1, 1, 2, 0, 1, 3, 1, 0, 1, 6, 0, 0, 0, 1, 7, 2, 1, 0, 0, 1, 14, 0, 0, 0, 0, 0, 1, 17, 3, 0, 1, 0, 0, 0, 1, 27, 0, 2, 0, 0, 0, 0, 0, 1, 34, 6, 0, 0, 1, 0, 0, 0, 0, 1, 55, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 63, 7, 3, 2, 0, 1, 0, 0, 0, 0, 0, 1, 100, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 1

Views

Author

Gary W. Adamson, Nov 28 2009

Keywords

Comments

Row sums = A000041 starting (1, 2, 3, 5, 7, 11, 15, ...).
T(n,k) is the number of partitions of n into parts with GCD = k. - Alois P. Heinz, Jun 06 2013

Examples

			First few rows of the triangle:
    1;
    1,  1;
    2,  0, 1;
    3,  1, 0, 1;
    6,  0, 0, 0, 1;
    7,  2, 1, 0, 0, 1;
   14,  0, 0, 0, 0, 0, 1;
   17,  3, 0, 1, 0, 0, 0, 1;
   27,  0, 2, 0, 0, 0, 0, 0, 1;
   34,  6, 0, 0, 1, 0, 0, 0, 0, 1;
   55,  0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
   63,  7, 3, 2, 0, 1, 0, 0, 0, 0, 0, 1;
  100,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
  119, 14, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1;
  167,  0, 6, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
  209, 17, 0, 3, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1;
  296,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
  ...
		

Crossrefs

Cf. A256067 (the same for LCM).

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i=1, x,
          b(n, i-1)+(p-> add(coeff(p, x, t)*x^igcd(t, i),
          t=0..degree(p)))(add(b(n-i*j, i-1), j=1..n/i))))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=1..n))(b(n$2)):
    seq(T(n), n=1..17);  # Alois P. Heinz, Mar 29 2015
  • Mathematica
    b[n_, i_] := b[n, i] = If[n==0, 1, If[i==1, x, b[n, i-1] + Function[{p}, Sum[Coefficient[p, x, t]*x^GCD[t, i], {t, 0, Exponent[p, x]}]][Sum[b[n - i*j, i-1], {j, 1, n/i}]]]]; T[n_] := Function[{p}, Table[Coefficient[p, x, i], {i, 1, n}]][b[n, n]]; Table[T[n], {n, 1, 17}] // Flatten (* Jean-François Alcover, Jan 08 2016, after Alois P. Heinz *)

Formula

Mobius transform of triangle A168021 = an infinite lower triangular matrix with aerated variants of A000837 in each column; where A000837 = the Mobius transform of the partition numbers, A000041.

Extensions

Corrected and extended by Alois P. Heinz, Jun 06 2013

A009490 Number of distinct orders of permutations of n objects; number of nonisomorphic cyclic subgroups of symmetric group S_n.

Original entry on oeis.org

1, 1, 2, 3, 4, 6, 6, 9, 11, 14, 16, 20, 23, 27, 31, 35, 43, 47, 55, 61, 70, 78, 88, 98, 111, 123, 136, 152, 168, 187, 204, 225, 248, 271, 296, 325, 356, 387, 418, 455, 495, 537, 581, 629, 678, 732, 787, 851, 918, 986, 1056, 1133, 1217, 1307, 1399, 1498, 1600, 1708, 1823
Offset: 0

Views

Author

Keywords

Comments

Also number of different LCM's of partitions of n.
a(n) <= A023893(n), which counts the nonisomorphic Abelian subgroups of S_n. - M. F. Hasler, May 24 2013

Crossrefs

Cf. A051613 (first differences), A000792, A000793, A034891, A051625 (all cyclic subgroups), A256067.

Programs

  • Maple
    b:= proc(n,i) option remember; local p;
          p:= `if`(i<1, 1, ithprime(i));
          `if`(n=0 or i<1, 1, b(n, i-1)+
          add(b(n-p^j, i-1), j=1..ilog[p](n)))
        end:
    a:= n-> b(n, numtheory[pi](n)):
    seq(a(n), n=0..100);  # Alois P. Heinz, Feb 15 2013
  • Mathematica
    Table[ Length[ Union[ Apply[ LCM, Partitions[ n ], 1 ] ] ], {n, 30} ]
    f[n_] := Length@ Union[LCM @@@ IntegerPartitions@ n]; Array[f, 60, 0]
    (* Caution, the following is Extremely Slow and Resource Intensive *) CoefficientList[ Series[ Expand[ Product[1 + Sum[x^(Prime@ i^k), {k, 4}], {i, 10}]/(1 - x)], {x, 0, 30}], x]
    b[n_, i_] := b[n, i] = Module[{p}, p = If[i<1, 1, Prime[i]]; If[n == 0 || i<1, 1, b[n, i-1]+Sum[b[n-p^j, i-1], {j, 1, Log[p, n]}]]]; a[n_] := b[n, PrimePi[n]]; Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Feb 03 2014, after Alois P. Heinz *)
  • PARI
    /* compute David W. Wilson's g.f., needs <1 sec for 1000 terms */
    N=1000;  x='x+O('x^N); /* N terms */
    gf=1; /* generating function */
    { forprime(p=2,N,
        sm = 1;  pp=p;  /* sum;  prime power */
        while ( ppJoerg Arndt, Jan 19 2011 */

Formula

a(n) = Sum_{k=0..n} b(k), where b(k) is the number of partitions of k into distinct prime power parts (1 excluded) (A051613). - Vladeta Jovovic
G.f.: (Product_{p prime} (1 + Sum_{k >= 1} x^(p^k))) / (1-x). - David W. Wilson, Apr 19 2000

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

A181844 Sum over all partitions of n of the LCM of the parts.

Original entry on oeis.org

1, 1, 3, 6, 12, 23, 38, 73, 118, 198, 318, 530, 819, 1298, 1974, 2975, 4516, 6698, 9980, 14550, 21186, 30304, 43503, 62030, 87908, 123292, 172543, 239720, 331688, 458198, 629376, 860332, 1168172, 1583176, 2138438, 2876283, 3859770, 5159886, 6863702, 9112356
Offset: 0

Views

Author

Peter Luschny, Dec 07 2010

Keywords

Comments

Old name was: Row sums of A181842.

Crossrefs

Cf. A078392 (the same for GCD), A181843, A181842, A256067, A256553, A256554, A306956.

Programs

  • Maple
    with(combstruct):
    a181844 := proc(n) local k,L,l,R,part;
    R := NULL; L := 0;
    for k from 1 to n do
       part := iterstructs(Partition(n),size=k):
       while not finished(part) do
          l := nextstruct(part);
          L := L + ilcm(op(l));
       od;
    od;
    L end:
    # second Maple program:
    b:= proc(n, i, r) option remember; `if`(n=0, r, `if`(i<1, 0,
           b(n, i-1, r)+b(n-i, min(i, n-i), ilcm(i, r))))
        end:
    a:= n-> b(n$2, 1):
    seq(a(n), n=0..42);  # Alois P. Heinz, Mar 18 2019
  • Mathematica
    t[n_, k_] := LCM @@@ IntegerPartitions[n, {n - k + 1}] // Total; a[n_] := Sum[t[n, k], {k, 1, n}]; Table[a[n], {n, 1, 32}] (* Jean-François Alcover, Jul 26 2013 *)

Formula

a(n) = Sum_{k>=0} k * A256067(n,k) = Sum_{k>=0} A256553(n,k)*A256554(n,k). - Alois P. Heinz, Apr 02 2015

Extensions

a(0)=1 prepended by Alois P. Heinz, Mar 29 2015
New name from Alois P. Heinz, Mar 18 2019

A256554 Number T(n,k) of cycle types of degree-n permutations having the k-th smallest possible order; triangle T(n,k), n>=0, 1<=k<=A009490(n), read by rows.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 3, 2, 2, 1, 2, 1, 3, 2, 2, 1, 3, 1, 1, 1, 1, 4, 2, 4, 1, 5, 1, 1, 1, 1, 1, 1, 4, 3, 4, 1, 7, 1, 1, 1, 2, 2, 1, 1, 1, 1, 5, 3, 6, 2, 9, 1, 2, 1, 3, 4, 1, 1, 1, 1, 1, 1, 5, 3, 6, 2, 12, 1, 2, 1, 4, 1, 6, 2, 2, 1, 2, 1, 1, 1, 2
Offset: 0

Views

Author

Alois P. Heinz, Apr 01 2015

Keywords

Comments

Sum_{k>=0} A256553(n,k)*T(n,k) = A181844(n).

Examples

			Triangle T(n,k) begins:
  1;
  1;
  1, 1;
  1, 1, 1;
  1, 2, 1, 1;
  1, 2, 1, 1, 1, 1;
  1, 3, 2, 2, 1, 2;
  1, 3, 2, 2, 1, 3, 1, 1, 1;
  1, 4, 2, 4, 1, 5, 1, 1, 1, 1, 1;
  1, 4, 3, 4, 1, 7, 1, 1, 1, 2, 2, 1, 1, 1;
  1, 5, 3, 6, 2, 9, 1, 2, 1, 3, 4, 1, 1, 1, 1, 1;
		

Crossrefs

Row sums give A000041.
Row lengths give A009490.
Columns k=1-9 give: A000012, A004526, A002264, A008642(n-4), A002266, A074752, A132270, A008643(n-8) for n>7, A008649(n-9) for n>8.
Last elements of rows give A074064.
Main diagonal gives A074761.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0 or i=1, x,
          b(n, i-1)+(p-> add(coeff(p, x, t)*x^ilcm(t, i),
          t=1..degree(p)))(add(b(n-i*j, i-1), j=1..n/i)))
        end:
    T:= n->(p->seq((h->`if`(h=0, [][], h))(coeff(p, x, i))
         , i=1..degree(p)))(b(n$2)):
    seq(T(n), n=0..12);
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0 || i == 1, x, b[n, i - 1] + Function[p, Sum[Coefficient[p, x, t]*x^LCM[t, i], {t, 1, Exponent[p, x]}]][Sum[b[n - i*j, i - 1], {j, 1, n/i}]]]; T[n_] := Function[p, Table[Function[h, If[h == 0, {{}, {}}, h]][Coefficient[p, x, i]], {i, 1, Exponent[p, x]}]][b[n, n]]; Table[T[n], {n, 0, 12}] // Flatten (* Jean-François Alcover, Jan 23 2017, translated from Maple *)

A074752 Number of combinatorially inequivalent cyclic subgroups of S_n of order 6. Number of partitions of n of order 6.

Original entry on oeis.org

1, 2, 3, 5, 7, 9, 12, 16, 19, 24, 29, 34, 40, 48, 54, 63, 72, 81, 91, 104, 114, 128, 142, 156, 171, 190, 205, 225, 245, 265, 286, 312, 333, 360, 387, 414, 442, 476, 504, 539, 574, 609, 645, 688, 724, 768, 812, 856, 901, 954, 999, 1053, 1107, 1161, 1216, 1280
Offset: 5

Views

Author

Vladeta Jovovic, Sep 28 2002

Keywords

Comments

Two permutation groups are combinatorially equivalent iff they have the same cycle index. Order of partition is lcm of its parts.

Crossrefs

Column k=6 of A256067, A256554.

Programs

  • Mathematica
    LinearRecurrence[{1,1,0,-1,-1,2,-1,-1,0,1,1,-1},{1,2,3,5,7,9,12,16,19,24,29,34},60] (* Harvey P. Dale, May 23 2020 *)

Formula

G.f.: x^5*(1+x-x^6)/((x-1)*(x^2-1)*(x^3-1)*(x^6-1)). More generally, g.f. for number of partitions of order d is Sum_{i divides d} mu(d/i)*1/Product_{j divides i} (1-x^j).

A256553 Triangle T(n,k) in which the n-th row contains the increasing list of distinct orders of degree-n permutations; n>=0, 1<=k<=A009490(n).

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7, 10, 12, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 20, 21, 30
Offset: 0

Views

Author

Alois P. Heinz, Apr 01 2015

Keywords

Examples

			Triangle T(n,k) begins:
  1;
  1;
  1, 2;
  1, 2, 3;
  1, 2, 3, 4;
  1, 2, 3, 4, 5, 6;
  1, 2, 3, 4, 5, 6;
  1, 2, 3, 4, 5, 6, 7, 10, 12;
  1, 2, 3, 4, 5, 6, 7,  8, 10, 12, 15;
  1, 2, 3, 4, 5, 6, 7,  8,  9, 10, 12, 14, 15, 20;
  1, 2, 3, 4, 5, 6, 7,  8,  9, 10, 12, 14, 15, 20, 21, 30;
		

Crossrefs

Row sums give A060179.
Row lengths give A009490.
Last elements of rows give A000793.
Main diagonal gives A000027.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0 or i=1, x,
          b(n, i-1)+(p-> add(coeff(p, x, t)*x^ilcm(t, i),
          t=1..degree(p)))(add(b(n-i*j, i-1), j=1..n/i)))
        end:
    T:= n->(p->seq((h->`if`(h=0, [][], i))(coeff(p, x, i))
         , i=1..degree(p)))(b(n$2)):
    seq(T(n), n=0..12);
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0 || i == 1, x,
         b[n, i - 1] + Function[p, Sum[Coefficient[p, x, t]*x^LCM[t, i],
         {t, 1, Exponent[p, x]}]][Sum[b[n - i*j, i - 1], {j, 1, n/i}]]];
    T[n_] := Function[p, Table[Function[h, If[h == 0, Nothing, i]][
         Coefficient[p, x, i]], {i, 1, Exponent[p, x]}]][b[n, n]];
    Table[T[n], {n, 0, 12}] // Flatten (* Jean-François Alcover, Jul 15 2021, after Alois P. Heinz *)

Formula

Sum_{k>=0} T(n,k)*A256554(n,k) = A181844(n).
T(n,k) = k for n>0 and 1<=k<=n.

A258470 Number of partitions of n of order 10.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 4, 6, 7, 9, 11, 13, 16, 18, 21, 25, 28, 33, 36, 41, 46, 51, 57, 62, 68, 76, 82, 91, 97, 106, 115, 124, 134, 143, 153, 166, 176, 190, 200, 214, 228, 242, 257, 271, 286, 305, 320, 340, 355, 375, 395, 415, 436, 456, 477, 503, 524
Offset: 0

Views

Author

Alois P. Heinz, May 31 2015

Keywords

Crossrefs

Column k=10 of A256067.

Formula

G.f.: -(x^10-x^3-1)*x^7/((x-1)*(x^2-1)*(x^5-1)*(x^10-1)).
Showing 1-9 of 9 results.