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.

A079640 Matrix product of unsigned Stirling1-triangle |A008275(n,k)| and unsigned Lah-triangle |A008297(n,k)|.

Original entry on oeis.org

1, 3, 1, 14, 9, 1, 88, 83, 18, 1, 694, 860, 275, 30, 1, 6578, 10084, 4245, 685, 45, 1, 72792, 132888, 69244, 14735, 1435, 63, 1, 920904, 1950024, 1209880, 318969, 41020, 2674, 84, 1, 13109088, 31580472, 22715972, 7133784, 1137549, 98028, 4578, 108, 1
Offset: 1

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Author

Vladeta Jovovic, Jan 30 2003

Keywords

Comments

Also the Bell transform of A007840(n+1). For the definition of the Bell transform see A264428. - Peter Luschny, Jan 26 2016

Examples

			1; 3,1; 14,9,1; 88,83,18,1; 694,860,275,30,1; 6578,10084,4245,685,45,1; ...
		

Crossrefs

Cf. A007840 (first column).

Programs

  • Maple
    # The function BellMatrix is defined in A264428.
    # Adds (1, 0, 0, 0, ..) as column 0.
    BellMatrix(n -> add(k!*abs(combinat:-stirling1(n+1, k)), k=0..n+1), 9); # Peter Luschny, Jan 26 2016
  • Mathematica
    BellMatrix[f_Function, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len - 1}, {k, 0, len - 1}]];
    rows = 12;
    M = BellMatrix[Function[n, Sum[k!*Abs[StirlingS1[n+1, k]], {k, 0, n+1}]], rows];
    Table[M[[n, k]], {n, 2, rows}, {k, 2, n}] // Flatten (* Jean-François Alcover, Jun 26 2018, after Peter Luschny *)

Formula

T(n, k) = Sum_{i=k..n} |A008275(n, i)| * |A008297(i, k)|.
E.g.f.: (1-x)^(-y/(1+log(1-x))). - Vladeta Jovovic, Nov 22 2003