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.

A203306 Vandermonde determinant of (1!, 2!, 3!, ..., n!).

Original entry on oeis.org

1, 1, 1, 20, 182160, 27993556039680, 4308936629569882673577984000, 58707314863972899718827044647532534690532556800000, 8707001005945253804913483804375384209011420702238388319242163029949808640000000000
Offset: 0

Views

Author

Clark Kimberling, Jan 01 2012

Keywords

Comments

Each term divides its successor, as in A203308.

Crossrefs

Cf. A203308.

Programs

  • Magma
    F:= Factorial; [1,1] cat [(&*[(&*[F(k+1) - F(j): j in [1..k]]): k in [1..n-1]]): n in [2..20]]; // G. C. Greubel, Aug 30 2023
    
  • Maple
    with(LinearAlgebra):
    a:= n-> Determinant(VandermondeMatrix([i!$i=1..n])):
    seq(a(n), n=0..10);  # Alois P. Heinz, Jul 23 2017
  • Mathematica
    f[j_]:= j!; z = 10;
    v[n_]:= Product[Product[f[k] - f[j], {j,k-1}], {k,2,n}]
    Table[v[n], {n,0,z}]        (* A203306 *)
    Table[v[n+1]/v[n], {n,z}]   (* A203308 *)
  • Python
    from sympy import factorial, prod
    f = factorial
    def v(n): return 1 if n<2 else prod(f(k) - f(j) for k in range(2, n + 1) for j in range(1, k))
    print([v(n) for n in range(11)]) # Indranil Ghosh, Jul 24 2017
    
  • SageMath
    f=factorial; [product(product(f(k+1) - f(j) for j in range(1,k+1)) for k in range(1,n)) for n in range(21)] # G. C. Greubel, Aug 30 2023

Formula

a(n) ~ c * (2*Pi)^(n*(n-1)/4) * n^(n^3/3 + n^2/4 - 7*n/12 - 11/8) / exp(4*n^3/9 - n^2/8 - n), where c = A323720 = 0.29363504888070220142364974947015983077985979... - Vaclav Kotesovec, Jan 25 2019

Extensions

a(0)=1 prepended by Alois P. Heinz, Jul 23 2017
Offset corrected by Vaclav Kotesovec, Jan 25 2019