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.

A144633 Triangle of 3-restricted Stirling numbers of the first kind (T(n,k), 0 <= k <= n), read by rows.

Original entry on oeis.org

1, 0, 1, 0, -1, 1, 0, 2, -3, 1, 0, -5, 11, -6, 1, 0, 10, -45, 35, -10, 1, 0, 35, 175, -210, 85, -15, 1, 0, -910, -315, 1225, -700, 175, -21, 1, 0, 11935, -6265, -5670, 5565, -1890, 322, -28, 1, 0, -134750, 139755, -5005, -39270, 19425, -4410, 546, -36, 1
Offset: 0

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Author

N. J. A. Sloane, Jan 21 2009

Keywords

Comments

Definition: take the triangle in A144385, write it as an (infinite) upper triangular square matrix, invert it and transpose it.
The Bell transform of A144636(n+1). Also the inverse Bell transform of the sequence "g(n) = 1 if n<3 else 0". For the definition of the Bell transform see A264428. - Peter Luschny, Jan 19 2016

Examples

			Triangle begins:
1;
0,    1;
0,   -1,    1;
0,    2,   -3,    1;
0,   -5,   11,   -6,    1;
0,   10,  -45,   35,  -10,   1;
0,   35,  175, -210,   85, -15,   1;
0, -910, -315, 1225, -700, 175, -21,  1;
		

References

  • J. Y. Choi and J. D. H. Smith, On the combinatorics of multi-restricted numbers, Ars. Com., 75(2005), pp. 44-63.

Crossrefs

For another version of this triangle see A144634.
Columns give A144636-A144639.
Cf. A144402.

Programs

  • Maple
    A:= proc(n,k) option remember; if n=k then 1 elif k A(i-1, j-1))^(-1) end:
    T:= (n,k)-> M(n+1)[k+1, n+1]:
    seq(seq(T(n,k), k=0..n), n=0..12); # Alois P. Heinz, Oct 23 2009
  • Mathematica
    max = 10; t[n_, n_] = 1; t[n_ /; n >= 0, k_] /; (0 <= k <= 3*n) := t[n, k] = t[n-1, k-1] + (k-1)*t[n-1, k-2] + (1/2)*(k-1)*(k-2)*t[n-1, k-3]; t[, ] = 0; A144633 = Table[t[n, k], {n, 0, max}, {k, 0, max}] // Inverse // Transpose; Table[A144633[[n, k]], {n, 1, max}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jan 14 2014 *)
  • Sage
    # uses[bell_matrix from A264428]
    bell_matrix(lambda n: A144636(n+1), 10) # Peter Luschny, Jan 18 2016

Extensions

Corrected and extended by Alois P. Heinz, Oct 23 2009