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.

A111888 Eighth column of triangle A112492 (inverse scaled Pochhammer symbols).

Original entry on oeis.org

1, 109584, 7245893376, 381495483224064, 17810567950611972096, 778101042571221893382144, 32762625292956765972873609216, 1351813956241264848815287984717824
Offset: 0

Views

Author

Wolfdieter Lang, Sep 12 2005

Keywords

Comments

Also continuation of family of Differences of reciprocals of unity. See A001242, A111887 and triangle A008969.

Crossrefs

Also right-hand column 7 in triangle A008969.

Programs

  • Magma
    A111888:= func< n | (-1)*Factorial(8)^n*(&+[(-1)^j*Binomial(8,j)/j^n : j in [1..8]]) >;
    [A111888(n): n in [0..30]]; // G. C. Greubel, Jul 24 2023
    
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, (k+1)^(n-k)*T[n-1,k-1] +k!*T[n-1,k]]; (* T = A112492 *)
    Table[T[n+7,7], {n,0,30}] (* G. C. Greubel, Jul 24 2023 *)
  • PARI
    a(n) = -((8!)^n)*sum(j=1, 8, ((-1)^j)*binomial(8, j)/j^n); \\ Michel Marcus, Apr 28 2020
    
  • SageMath
    @CachedFunction
    def T(n,k): # T = A112492
        if (k==0 or k==n): return 1
        else: return (k+1)^(n-k)*T(n-1,k-1) + factorial(k)*T(n-1,k)
    def A111888(n): return T(n+7,7)
    [A111888(n) for n in range(31)] # G. C. Greubel, Jul 24 2023

Formula

G.f.: 1/Product_{j=1..8} 1-8!*x/j.
a(n) = -((8!)^n) * Sum_{j=1..8} (-1)^j*binomial(8, j)/j^n, n>=0.
a(n) = A112492(n+7, 8), n>=0.