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 1-3 of 3 results.

A130273 Refines A075197(n): number of partitions of n balls of n colors. The refinement has shape A000041(n).

Original entry on oeis.org

1, 4, 2, 9, 24, 5, 20, 84, 54, 132, 15, 35, 240, 320, 630, 780, 720, 52, 66, 570, 870, 2280, 465, 6240, 4440, 1320, 8280, 4050, 203, 105, 1260, 1974, 6720, 2394, 20580, 19740, 14385, 11445, 83160, 31080, 34860, 77910, 23772, 877, 176, 2520, 4312, 17640, 5432
Offset: 1

Views

Author

Alford Arnold, May 19 2007

Keywords

Comments

a(n) can be calculated by resorting A035206 into Mathematica order vice AS1 ordering and then multiplying term by term with A096443(n).

Examples

			The array begins
1
4 2
9 24 5
20 84 54 132 15
...
Row three is (9,24,5) because there are (3, 4,5) cases; and we have (3, 6,1) ways to pick 1,2 or 3 colors.
		

Crossrefs

A075196 Table T(n,k) by antidiagonals: T(n,k) = number of partitions of n balls of k colors.

Original entry on oeis.org

1, 2, 2, 3, 6, 3, 4, 12, 14, 5, 5, 20, 38, 33, 7, 6, 30, 80, 117, 70, 11, 7, 42, 145, 305, 330, 149, 15, 8, 56, 238, 660, 1072, 906, 298, 22, 9, 72, 364, 1260, 2777, 3622, 2367, 591, 30, 10, 90, 528, 2198, 6174, 11160, 11676, 6027, 1132, 42, 11, 110, 735, 3582, 12292, 28784, 42805, 36450, 14873, 2139, 56
Offset: 1

Views

Author

Christian G. Bower, Sep 07 2002

Keywords

Comments

For k>=1, n->infinity is log(T(n,k)) ~ (1+1/k) * k^(1/(k+1)) * Zeta(k+1)^(1/(k+1)) * n^(k/(k+1)). - Vaclav Kotesovec, Mar 08 2015

Examples

			Square array T(n,k) begins:
  1,  2,   3,    4,    5, ...
  2,  6,  12,   20,   30, ...
  3, 14,  38,   80,  145, ...
  5, 33, 117,  305,  660, ...
  7, 70, 330, 1072, 2777, ...
		

Crossrefs

Rows 1-3: A000027, A002378, A162147.
Main diagonal: A075197.
Cf. A255903.

Programs

  • Maple
    with(numtheory):
    A:= proc(n, k) option remember; local d, j;
          `if`(n=0, 1, add(add(d*binomial(d+k-1, k-1),
           d=divisors(j)) *A(n-j, k), j=1..n)/n)
        end:
    seq(seq(A(n, 1+d-n), n=1..d), d=1..12);  # Alois P. Heinz, Sep 26 2012
  • Mathematica
    Transpose[Table[nn=6;p=Product[1/(1- x^i)^Binomial[i+n,n],{i,1,nn}];Drop[CoefficientList[Series[p,{x,0,nn}],x],1],{n,0,nn}]]//Grid  (* Geoffrey Critzer, Sep 27 2012 *)

Formula

T(n,k) = Sum_{i=0..k} C(k,i) * A255903(n,i). - Alois P. Heinz, Mar 10 2015

A344098 a(n) = [x^n] Product_{k>=1} (1 + x^k)^binomial(k+n-1,n-1).

Original entry on oeis.org

1, 1, 4, 29, 221, 2027, 21022, 242209, 3060262, 41936745, 618154670, 9735013136, 162892047930, 2882449728121, 53727527279464, 1051276401060921, 21529017626095851, 460231878244308738, 10246160509840187387, 237067632496414877363, 5689786581042000827057, 141415234722601777758232
Offset: 0

Views

Author

Ilya Gutkovskiy, May 09 2021

Keywords

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[Product[(1 + x^k)^Binomial[k + n - 1, n - 1], {k, 1, n}], {x, 0, n}], {n, 0, 21}]
    A[n_, k_] := A[n, k] = If[n == 0, 1, (1/n) Sum[Sum[(-1)^(j/d + 1) d Binomial[d + k - 1, k - 1], {d, Divisors[j]}] A[n - j, k], {j, 1, n}]]; a[n_] := A[n, n]; Table[a[n], {n, 0, 21}]
Showing 1-3 of 3 results.