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 1-5 of 5 results.

A089259 Expansion of Product_{m>=1} 1/(1-x^m)^A000009(m).

Original entry on oeis.org

1, 1, 2, 4, 7, 12, 22, 36, 61, 101, 166, 267, 433, 686, 1088, 1709, 2671, 4140, 6403, 9824, 15028, 22864, 34657, 52288, 78646, 117784, 175865, 261657, 388145, 573936, 846377, 1244475, 1825170, 2669776, 3895833, 5671127, 8236945, 11936594, 17261557, 24909756
Offset: 0

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Author

N. J. A. Sloane, Dec 23 2003

Keywords

Comments

Number of complete set partitions of the integer partitions of n. This is the Euler transform of A000009. If we change the combstruct command from unlabeled to labeled, then we get A000258. - Thomas Wieder, Aug 01 2008
Number of set multipartitions (multisets of sets) of integer partitions of n. Also a(n) < A270995(n) for n>5. - Gus Wiseman, Apr 10 2016

Examples

			From _Gus Wiseman_, Oct 22 2018: (Start)
The a(6) = 22 set multipartitions of integer partitions of 6:
  (6)  (15)    (123)      (12)(12)      (1)(1)(1)(12)    (1)(1)(1)(1)(1)(1)
       (24)    (1)(14)    (1)(1)(13)    (1)(1)(1)(1)(2)
       (1)(5)  (1)(23)    (1)(2)(12)
       (2)(4)  (2)(13)    (1)(1)(1)(3)
       (3)(3)  (3)(12)    (1)(1)(2)(2)
               (1)(1)(4)
               (1)(2)(3)
               (2)(2)(2)
(End)
		

Crossrefs

Programs

  • Maple
    with(combstruct): A089259:= [H, {H=Set(T, card>=1), T=PowerSet (Sequence (Z, card>=1), card>=1)}, unlabeled]; 1, seq (count (A089259, size=j), j=1..16); # Thomas Wieder, Aug 01 2008
    # second Maple program:
    with(numtheory):
    b:= proc(n, i)
          if n<0 or n>i*(i+1)/2 then 0
        elif n=0 then 1
        elif i<1 then 0
        else b(n,i):= b(n-i, i-1) +b(n, i-1)
          fi
        end:
    a:= proc(n) option remember; `if` (n=0, 1,
           add(add(d* b(d, d), d=divisors(j)) *a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..100);  # Alois P. Heinz, Nov 11 2011
  • Mathematica
    max = 40; CoefficientList[Series[Product[1/(1-x^m)^PartitionsQ[m], {m, 1, max}], {x, 0, max}], x] (* Jean-François Alcover, Mar 24 2014 *)
    b[n_, i_] := b[n, i] = Which[n<0 || n>i*(i+1)/2, 0, n == 0, 1, i<1, 0, True, b[n-i, i-1] + b[n, i-1]]; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d* b[d, d], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 100} ] (* Jean-François Alcover, Feb 13 2016, after Alois P. Heinz *)
  • PARI
    EulerT(v)={Vec(exp(x*Ser(dirmul(v,vector(#v,n,1/n))))-1, -#v)}
    seq(n)={concat([1], EulerT(Vec(eta(x^2 + O(x*x^n))/eta(x + O(x*x^n)) - 1)))} \\ Andrew Howroyd, Oct 26 2018

A285229 Expansion of g.f. Product_{j>=1} 1/(1-y*x^j)^A000009(j), triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 2, 1, 1, 0, 2, 3, 1, 1, 0, 3, 4, 3, 1, 1, 0, 4, 8, 5, 3, 1, 1, 0, 5, 11, 10, 5, 3, 1, 1, 0, 6, 18, 16, 11, 5, 3, 1, 1, 0, 8, 25, 29, 18, 11, 5, 3, 1, 1, 0, 10, 38, 44, 34, 19, 11, 5, 3, 1, 1, 0, 12, 52, 72, 55, 36, 19, 11, 5, 3, 1, 1
Offset: 0

Views

Author

Alois P. Heinz, Apr 14 2017

Keywords

Examples

			T(n,k) is the number of multisets of exactly k partitions of positive integers into distinct parts with total sum of parts equal to n.
T(4,1) = 2: {4}, {31}.
T(4,2) = 3: {3,1}, {21,1}, {2,2}.
T(4,3) = 1: {2,1,1}.
T(4,4) = 1: {1,1,1,1}.
Triangle T(n,k) begins:
  1;
  0,  1;
  0,  1,  1;
  0,  2,  1,   1;
  0,  2,  3,   1,  1;
  0,  3,  4,   3,  1,  1;
  0,  4,  8,   5,  3,  1,  1;
  0,  5, 11,  10,  5,  3,  1,  1;
  0,  6, 18,  16, 11,  5,  3,  1,  1;
  0,  8, 25,  29, 18, 11,  5,  3,  1, 1;
  0, 10, 38,  44, 34, 19, 11,  5,  3, 1, 1;
  0, 12, 52,  72, 55, 36, 19, 11,  5, 3, 1, 1;
  0, 15, 75, 110, 96, 60, 37, 19, 11, 5, 3, 1, 1;
  ...
		

Crossrefs

Columns k=0..10 give: A000007, A000009 (for n>0), A320787, A320788, A320789, A320790, A320791, A320792, A320793, A320794, A320795.
Row sums give A089259.
T(2n,n) give A285230.

Programs

  • Maple
    with(numtheory):
    g:= proc(n) option remember; `if`(n=0, 1, add(add(
          `if`(d::odd, d, 0), d=divisors(j))*g(n-j), j=1..n)/n)
        end:
    b:= proc(n, i) option remember; expand(
          `if`(n=0, 1, `if`(i<1, 0, add(b(n-i*j, i-1)*
           x^j*binomial(g(i)+j-1, j), j=0..n/i))))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..n))(b(n$2)):
    seq(T(n), n=0..16);
  • Mathematica
    L[n_] := QPochhammer[x^2]/QPochhammer[x] + O[x]^n;
    A[n_] := Module[{c = L[n]}, CoefficientList[#, y]& /@ CoefficientList[ 1/Product[(1 - x^k*y + O[x]^n)^SeriesCoefficient[c, {x, 0, k}], {k, 1, n}], x]];
    A[12] // Flatten (* Jean-François Alcover, Jan 19 2020, after Andrew Howroyd *)
    g[n_] := g[n] = If[n==0, 1, Sum[Sum[If[OddQ[d], d, 0], {d, Divisors[j]}]* g[n - j], {j, 1, n}]/n];
    b[n_, i_] := b[n, i] = If[n==0, 1, If[i<1, 0, Sum[b[n - i*j, i - 1]*x^j* Binomial[g[i] + j - 1, j], {j, 0, n/i}]]];
    T[n_] := CoefficientList[b[n, n] + O[x]^(n+1), x];
    T /@ Range[0, 16] // Flatten (* Jean-François Alcover, Dec 14 2020, after Alois P. Heinz *)
  • PARI
    L(n)={eta(x^2 + O(x*x^n))/eta(x + O(x*x^n))}
    A(n)={my(c=L(n), v=Vec(1/prod(k=1, n, (1 - x^k*y + O(x*x^n))^polcoef(c,k)))); vector(#v, n, Vecrev(v[n],n))}
    {my(T=A(12)); for(n=1, #T, print(T[n]))} \\ Andrew Howroyd, Dec 29 2019

Formula

G.f.: Product_{j>=1} 1/(1-y*x^j)^A000009(j).

A360764 Number T(n,k) of sets of nonempty strict integer partitions with a total of k parts and total sum of n; triangle T(n,k), n>=0, 0<=k<=max(i:T(n,i)>0), read by rows.

Original entry on oeis.org

1, 0, 1, 0, 1, 0, 1, 2, 0, 1, 2, 1, 0, 1, 4, 2, 0, 1, 4, 6, 1, 0, 1, 6, 8, 4, 0, 1, 6, 13, 9, 1, 0, 1, 8, 18, 16, 6, 0, 1, 8, 24, 29, 13, 2, 0, 1, 10, 30, 43, 29, 6, 0, 1, 10, 39, 64, 52, 19, 1, 0, 1, 12, 46, 89, 89, 42, 7, 0, 1, 12, 56, 122, 139, 85, 22, 1
Offset: 0

Views

Author

Alois P. Heinz, Feb 19 2023

Keywords

Comments

T(n,k) is defined for all n >= 0 and k >= 0. Terms that are not in the triangle are zero.

Examples

			T(6,1) = 1: {[6]}.
T(6,2) = 4: {[1],[5]}, {[2],[4]}, {[1,5]}, {[2,4]}.
T(6,3) = 6: {[1,2,3]}, {[1],[1,4]}, {[1],[2,3]}, {[2],[1,3]}, {[3],[1,2]}, {[1],[2],[3]}.
T(6,4) = 1: {[1],[2],[1,2]}.
Triangle T(n,k) begins:
  1;
  0, 1;
  0, 1;
  0, 1,  2;
  0, 1,  2,  1;
  0, 1,  4,  2;
  0, 1,  4,  6,  1;
  0, 1,  6,  8,  4;
  0, 1,  6, 13,  9,  1;
  0, 1,  8, 18, 16,  6;
  0, 1,  8, 24, 29, 13,  2;
  0, 1, 10, 30, 43, 29,  6;
  0, 1, 10, 39, 64, 52, 19, 1;
  ...
		

Crossrefs

Columns k=0-2 give: A000007, A057427, A052928(n-1) for n>=3.
Row sums give A050342.

Programs

  • Maple
    h:= proc(n, i) option remember; expand(`if`(n=0, 1,
          `if`(i<1, 0, h(n, i-1)+x*h(n-i, min(n-i, i-1)))))
        end:
    g:= proc(n, i, j) option remember; expand(`if`(j=0, 1, `if`(i<0, 0, add(
          g(n, i-1, j-k)*x^(i*k)*binomial(coeff(h(n$2), x, i), k), k=0..j))))
        end:
    b:= proc(n, i) option remember; expand(`if`(n=0, 1,
         `if`(i<1, 0, add(b(n-i*j, i-1)*g(i$2, j), j=0..n/i))))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..degree(p)))(b(n$2)):
    seq(T(n), n=0..14);
  • Mathematica
    h[n_, i_] := h[n, i] = Expand[If[n == 0, 1, If[i < 1, 0, h[n, i - 1] + x*h[n - i, Min[n - i, i - 1]]]]];
    g[n_, i_, j_] := g[n, i, j] = Expand[If[j == 0, 1, If[i<0, 0, Sum[g[n, i - 1, j - k]*x^(i*k)*Binomial[Coefficient[h[n, n], x, i], k], {k, 0, j}]]]];
    b[n_, i_] := b[n, i] = Expand[If[n == 0, 1, If[i < 1, 0, Sum[b[n - i*j, i - 1]*g[i, i, j], {j, 0, n/i}]]]] ;
    T[n_] := CoefficientList[b[n, n], x];
    Table[T[n], {n, 0, 14}] // Flatten (* Jean-François Alcover, Nov 17 2023, after Alois P. Heinz *)

A360784 Number of multisets of nonempty strict integer partitions with a total of n parts and total sum of 2n.

Original entry on oeis.org

1, 1, 3, 8, 18, 39, 86, 175, 352, 688, 1318, 2472, 4576, 8322, 14959, 26560, 46657, 81130, 139866, 239047, 405496, 682891, 1142466, 1899344, 3139432, 5160455, 8438871, 13732292, 22242647, 35867937, 57597730, 92121145, 146775205, 232998683, 368579188, 581091003
Offset: 0

Views

Author

Alois P. Heinz, Feb 20 2023

Keywords

Examples

			a(3) = 8: {[1,2,3]}, {[1],[1,4]}, {[1],[2,3]}, {[2],[1,3]}, {[3],[1,2]}, {[1],[1],[4]}, {[1],[2],[3]}, {[2],[2],[2]}.
		

Crossrefs

Programs

  • Maple
    h:= proc(n, i) option remember; expand(`if`(n=0, 1,
          `if`(i<1, 0, h(n, i-1)+x*h(n-i, min(n-i, i-1)))))
        end:
    g:= proc(n, i, j) option remember; expand(`if`(j=0, 1, `if`(i<0, 0, add(
          g(n, i-1, j-k)*x^(i*k)*binomial(coeff(h(n$2), x, i)+k-1, k), k=0..j))))
        end:
    b:= proc(n, i) option remember; expand(`if`(n=0, 1,
         `if`(i<1, 0, add(b(n-i*j, i-1)*g(i$2, j), j=0..n/i))))
        end:
    a:= n-> coeff(b(2*n$2), x, n):
    seq(a(n), n=0..35);
  • Mathematica
    h[n_, i_] := h[n, i] = Expand[If[n == 0, 1, If[i < 1, 0, h[n, i - 1] + x*h[n - i, Min[n - i, i - 1]]]]];
    g[n_, i_, j_] := g[n, i, j] = Expand[If[j == 0, 1, If[i < 0, 0, Sum[g[n, i - 1, j - k]*x^(i*k)*Binomial[Coefficient[h[n, n], x, i] + k - 1, k], {k, 0, j}]]]];
    b[n_, i_] := b[n, i] = Expand[If[n == 0, 1, If[i < 1, 0, Sum[b[n - i*j, i - 1]*g[i, i, j], {j, 0, n/i}]]]];
    a[n_] := Coefficient[b[2 n, 2 n], x, n];
    Table[a[n], {n, 0, 35}] (* Jean-François Alcover, Nov 21 2023, after Alois P. Heinz *)

Formula

a(n) = A360763(2n,n).

A360785 Number of multisets of nonempty strict integer partitions with a total of 2n parts and total sum of 3n.

Original entry on oeis.org

1, 2, 5, 12, 26, 54, 112, 220, 427, 812, 1518, 2790, 5074, 9096, 16144, 28360, 49367, 85180, 145867, 247886, 418426, 701702, 1169673, 1938498, 3195497, 5240386, 8552308, 13892638, 22468406, 36184636, 58040397, 92737842, 147631545, 234184172, 370215442, 583343070
Offset: 0

Views

Author

Alois P. Heinz, Feb 20 2023

Keywords

Examples

			a(2) = 5: {[1],[1],[1],[3]}, {[1],[1],[2],[2]}, {[1],[1],[1,3]}, {[1],[2],[1,2]}, {[1,2],[1,2]}.
		

Crossrefs

Programs

  • Maple
    h:= proc(n, i) option remember; expand(`if`(n=0, 1,
          `if`(i<1, 0, h(n, i-1)+x*h(n-i, min(n-i, i-1)))))
        end:
    g:= proc(n, i, j) option remember; expand(`if`(j=0, 1, `if`(i<0, 0, add(
          g(n, i-1, j-k)*x^(i*k)*binomial(coeff(h(n$2), x, i)+k-1, k), k=0..j))))
        end:
    b:= proc(n, i) option remember; expand(`if`(n=0, 1,
         `if`(i<1, 0, add(b(n-i*j, i-1)*g(i$2, j), j=0..n/i))))
        end:
    a:= n-> coeff(b(3*n$2), x, 2*n):
    seq(a(n), n=0..35);
  • Mathematica
    h[n_, i_] := h[n, i] = Expand[If[n == 0, 1, If[i < 1, 0, h[n, i - 1] + x*h[n - i, Min[n - i, i - 1]]]]];
    g[n_, i_, j_] := g[n, i, j] = Expand[If[j == 0, 1, If[i < 0, 0, Sum[g[n, i - 1, j - k]*x^(i*k)*Binomial[Coefficient[h[n, n], x, i] + k - 1, k], {k, 0, j}]]]];
    b[n_, i_] := b[n, i] = Expand[If[n == 0, 1, If[i < 1, 0, Sum[b[n - i*j, i - 1]*g[i, i, j], {j, 0, n/i}]]]];
    a[n_] := Coefficient[b[3n, 3n], x, 2n];
    Table[a[n], {n, 0, 35}] (* Jean-François Alcover, Dec 09 2023, after Alois P. Heinz *)

Formula

a(n) = A360763(3n,2n) = A360763(3n+j,2n+j) for j>=0.
a(n) = max({ A360763(k,k-n) : k>=n }).
Showing 1-5 of 5 results.