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.

A232788 A232773(n) / A006882(n): Permanent of the n X n matrix with elements [1,2,...,n^2], divided by n!!.

Original entry on oeis.org

1, 1, 5, 150, 6932, 965380, 143299890, 51176650000, 16737737386944, 11806879466638656, 7023172771916784000, 8447153882019234307200, 8134080139379917205277696, 15176253254155788712392633600, 21875035292051870323313614135440, 59270306784445546617788929301760000
Offset: 0

Views

Author

M. F. Hasler, Nov 30 2013

Keywords

Comments

Limit n->infinity a(n)^(1/n)/n^(5/2) = exp(-3/2). - Vaclav Kotesovec, Nov 08 2014

Crossrefs

Programs

  • Maple
    with(combinat):
    a:= n-> (-1)^n *add(n^k *stirling1(n, n-k)*stirling1(n+1, k+1)
            *(n-k)!* k!, k=0..n)/doublefactorial(n):
    seq(a(n), n=0..20);  # Alois P. Heinz, Dec 02 2013
  • Mathematica
    Flatten[{1,Table[(-1)^n*Sum[n^k*StirlingS1[n,n-k]*StirlingS1[n+1,k+1]*(n-k)!*k!,{k,0,n}]/n!!,{n,1,20}]}] (* Vaclav Kotesovec, Nov 08 2014 *)
  • PARI
    n->(-1)^n*sum(k=0,n,n^k*stirling(n,n-k)*stirling(n+1,k+1)*(n-k)!*k!)/A006882(n)

Extensions

a(0)=1 inserted by Alois P. Heinz, Dec 02 2013