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.

A137341 a(n) = n! * A000110(n) where A000110 is the sequence of Bell numbers.

Original entry on oeis.org

1, 1, 4, 30, 360, 6240, 146160, 4420080, 166924800, 7673823360, 420850080000, 27086342976000, 2018319704755200, 172142484203289600, 16642276683198566400, 1808459441303074560000, 219273812138054209536000, 29473992420094651613184000
Offset: 0

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Author

David W. K. Yeung, Eric L. H. Ku and Patricia M. Yeung (wkyeung(AT)hkbu.edu.hk), Apr 08 2008

Keywords

Comments

Cooperative games are frequently formulated in terms of partition functions. In particular, the set of players may be divided into various coalitions forming partitions with different coalition structures. This recursive sequence identifies the number of partitions in an n-player game where the position of the individual player counts.
Lists of sublists of total size n with up to n different 1s, up to n-1 different 2s, ... generated by successive insertion. Sublists stay ordered as inserted. See example field for illustration. - Olivier Gérard, Aug 12 2016

Examples

			a(0) = 1;
a(1) = C(0,0)*a(0)*1!/0! = 1;
a(2) = C(1,1)*a(1)*2!/1! + C(1,0)*a(0)*2!/0! = 4;
a(3) = C(2,2)*a(2)*3!/2! + C(2,1)*a(1)*3!/1! + C(2,0)*a(0)*3!/0! = 30;
a(4) = C(3,3)*a(3)*4!/3! + C(3,2)*a(2)*4!/2! + C(3,1)*a(1)*4!/1! + C(3,0)*a(0)*4!/0! = 360.
From _Olivier Gérard_, Aug 12 2016: (Start)
Illustration as family of lists of sublists extending set partitions.
In this interpretation the lowercase letters allow us to distinguish between integers introduced at each iteration (or generation).
Construction from the family of size n to family of size n+1 is done by insertion.
Insertion is only possible at the end of a sublist or to create a new singleton sublist at the end of the list.
:
1: {{1a}}*
4: {{1a},{1b}}  {{1a,1b}}  {{1a,2b}}*  {{1a},{2b}}*
30: {{1a,1c},{1b}}     {{1a},{1b,1c}}     {{1a},{1b},{1c}}
....{{1a,2c},{1b}}     {{1a},{1b,2c}}     {{1a},{1b},{2c}}
....{{1a,3c},{1b}}     {{1a},{1b,3c}}     {{1a},{1b},{3c}}
....{{1a,1b,1c}}       {{1a,1b},{1c}}
....{{1a,1b,2c}}       {{1a,1b},{2c}}
....{{1a,1b,3c}}       {{1a,1b},{3c}}
....{{1a,2b,1c}}       {{1a,2b,2c}}       {{1a,2b,3c}}*
....{{1a,2b},{1c}}     {{1a,2b},{2c}}     {{1a,2b},{3c}}*
....{{1a,1c},{2b}}     {{1a},{2b,1c}}     {{1a},{2b},{1c}}
....{{1a,2c},{2b}}     {{1a},{2b,2c}}     {{1a},{2b},{2c}}
....{{1a,3c},{2b}}*    {{1a},{2b,3c}}*    {{1a},{2b},{3c}}*
:
The lists of sublists marked with * correspond to classical set partitions counted by Bell numbers A000110. (End)
		

References

  • W. Lucas and R. Thrall, N-person games in partition function form, Naval Research Logistics Quarterly X, pp. 281-298, 1963.

Crossrefs

Cf. A048800 = n!*A000110(n-1).
Main diagonal of A323099 and of A323128.

Programs

  • Maple
    b:= proc(n) option remember; `if`(n=0, 1,
          add(b(n-j)*binomial(n-1, j-1), j=1..n))
        end:
    a:= n-> b(n)*n!:
    seq(a(n), n=0..23);  # Alois P. Heinz, Aug 30 2019
  • Mathematica
    Table[n!*BellB[n],{n,0,20}] (* Vaclav Kotesovec, Mar 13 2014 *)
  • PARI
    Vec(serlaplace(serlaplace(exp(exp(O(x^20)+x)-1)))) \\ Joerg Arndt, Mar 13 2009
    
  • Python
    from sympy import bell, factorial
    [factorial(n) * bell(n) for n in range(101)] # Indranil Ghosh, Mar 20 2017
  • Sage
    [factorial(m) * bell_number(m) for m in range(17)]  # Zerinvary Lajos, Jul 06 2008
    

Formula

a(0) = 1; for n>0, a(n) = Sum_{j=0..n-1} binomial(n-1,j) * a(j) * n!/j!.
From the recurrence it follows that A'(x) = exp(x) * A(x) where A(x) = Sum_{k>=0} a(k) * x^k / k!^2. The solution to this differential equation is A(x) = exp(exp(x)). The expression in Joerg Arndt's PARI program follows from this. - Max Alekseyev, Mar 11 2009
a(n) ~ n^(2*n+1/2) * exp(n/LambertW(n)-1-2*n) * sqrt(2*Pi/(1+LambertW(n))) / LambertW(n)^n. - Vaclav Kotesovec, Mar 13 2014
a(n) = n! * Sum_{j=0..n} Stirling2(n,j). - Detlef Meya, Apr 11 2024

Extensions

Edited by N. J. A. Sloane, Sep 19 2009
More terms from Vincenzo Librandi, Mar 15 2014