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.

A137597 Triangle read by rows: A008277 * A007318.

Original entry on oeis.org

1, 2, 1, 5, 5, 1, 15, 22, 9, 1, 52, 99, 61, 14, 1, 203, 471, 385, 135, 20, 1, 877, 2386, 2416, 1140, 260, 27, 1, 4140, 12867, 15470, 9156, 2835, 455, 35, 1, 21147, 73681, 102215, 72590, 28441, 6230, 742, 44, 1
Offset: 1

Views

Author

Gary W. Adamson, Jan 29 2008

Keywords

Comments

Row sums = A035009 starting (1, 3, 11, 47, 227, ...).

Examples

			First few rows of the triangle:
    1;
    2,   1;
    5,   5,   1;
   15,  22,   9,   1;
   52,  99,  61,  14,  1;
  203, 471, 385, 135, 20, 1;
  ...
		

Crossrefs

Programs

  • Maple
    T:= (n, k)-> add(Stirling2(n, j)*binomial(j-1, k-1), j=k..n):
    seq(seq(T(n, k), k=1..n), n=1..10);  # Alois P. Heinz, Sep 03 2019
  • Mathematica
    Table[Sum[StirlingS2[n, j]*Binomial[j - 1, k - 1], {j, k, n}], {n, 9}, {k, n}] // Flatten (* Michael De Vlieger, Aug 31 2023 *)

Formula

A008277 * A007318 as infinite lower triangular matrices.