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.

A187555 Triangle read by rows, defined by T(n,k)=binomial(n,k)*|Stirling1(n,k)|, 0<=k<=n.

Original entry on oeis.org

1, 0, 1, 0, 2, 1, 0, 6, 9, 1, 0, 24, 66, 24, 1, 0, 120, 500, 350, 50, 1, 0, 720, 4110, 4500, 1275, 90, 1, 0, 5040, 37044, 56840, 25725, 3675, 147, 1, 0, 40320, 365904, 735392, 473830, 109760, 9016, 224, 1, 0, 362880, 3945024, 9922416, 8477784, 2828574, 381024, 19656, 324, 1, 0, 3628800, 46195920, 140724000, 151972800, 67869900, 13287330, 1134000, 39150, 450, 1
Offset: 0

Views

Author

Emanuele Munarini, Mar 11 2011

Keywords

Examples

			Triangle begins:
1
0,1
0,2,1
0,6,9,1
0,24,66,24,1
0,120,500,350,50,1
0,720,4110,4500,1275,90,1
0,5040,37044,56840,25725,3675,147,1
0,40320,365904,735392,473830,109760,9016,224,1
		

Crossrefs

Row sum sequence is A211210.

Programs

  • Maple
    seq(seq(binomial(n,k)*abs(combinat[stirling1](n,k)),k=0..n),n=0..8);
  • Mathematica
    Flatten[Table[
      Table[Binomial[n, k] Abs[StirlingS1[n, k]], {k, 0, n}], {n, 0, 10}], 1]
  • Maxima
    create_list(binomial(n,k)*abs(stirling1(n,k)),n,0,10,k,0,n);

Formula

a(n,k) = binomial(n,k)*A132393(n,k).

Extensions

Edited by Olivier Gérard, Oct 23 2012