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.

A156584 Triangle T(n,k) = SF(n+1)/(SF(n-k+1)*SF(k+1)) where SF(n) is the superfactorial A000178(n), read by rows.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 12, 12, 1, 1, 60, 240, 60, 1, 1, 360, 7200, 7200, 360, 1, 1, 2520, 302400, 1512000, 302400, 2520, 1, 1, 20160, 16934400, 508032000, 508032000, 16934400, 20160, 1, 1, 181440, 1219276800, 256048128000, 1536288768000, 256048128000, 1219276800, 181440, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 10 2009

Keywords

Examples

			Triangle begins as:
  1;
  1,     1;
  1,     3,        1;
  1,    12,       12,         1;
  1,    60,      240,        60,         1;
  1,   360,     7200,      7200,       360,        1;
  1,  2520,   302400,   1512000,    302400,     2520,     1;
  1, 20160, 16934400, 508032000, 508032000, 16934400, 20160, 1;
		

Crossrefs

Cf. A007318 (m=0), this sequence (m=1), A156764 (m=3).
Cf. A009963.

Programs

  • Maple
    SF := n -> mul(j!, j=0..n): T := (n,k) -> SF(n-1)/(SF(n-k)*SF(k)):
    seq(print(seq(T(n,k),k=1..n-1)),n=0..9); # Peter Luschny, Jan 24 2015
  • Mathematica
    (* First program *)
    b[n_, k_]:= If[k==0, n!, Product[Sum[(-1)^(i+j)*(j+1)*StirlingS1[j-1, i]*(k+1)^i, {i, 0, j-1}], {j, 1, n}]];
    T[n_, k_, m_] = If[n==0, 1, b[n, m]/(b[k, m]*b[n-k, m])];
    Table[T[n, k, 1], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Jun 20 2021 *)
    (* Second program *)
    f[n_, k_]:= If[k==0, n!, (-1)^n*(n+1)!*BarnesG[n+k+1]/(Gamma[k+1]^n*BarnesG[k+1])];
    T[n_, k_, m_]:= If[n==0, 1, f[n,m]/(f[k,m]*f[n-k,m])];
    Table[T[n,k,1], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Jun 20 2021 *)
  • Sage
    def f(n,k): return factorial(n) if (k==0) else (-1)^n*factorial(n+1)*product( rising_factorial(k+1, j) for j in (0..n-1) )
    def T(n,k,m): return 1 if (n==0) else f(n,m)/(f(k,m)*f(n-k,m))
    flatten([[T(n,k,1) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jun 21 2021

Formula

From G. C. Greubel, Jun 21 2021: (Start)
T(n, k) = BarnesG(n+3)/(BarnesG(k+3)*BarnesG(n-k+3)).
T(n, k, m) = f(n, m)/(f(k, m)*f(n-k, m)), with T(0, k, m) = 1, f(n, k) = (-1)^n*(n + 1)!*BarnesG(n+k+1)/(Gamma(k+1)^n*BarnesG(k+1)), f(n, 0) = n!, and m = 1. (End)

Extensions

New name and editing, Peter Luschny, Jan 24 2015