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.

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A203482 a(n) = Product_{1 <= i < j <= n} (i! + j!).

Original entry on oeis.org

1, 3, 168, 3276000, 877449500928000, 207244701437748852512194560000, 4000516840149319128119305958853265913416777728000000, 796608816253064941944831363792070377592412324940256242675178274726476775424000000000
Offset: 1

Views

Author

Clark Kimberling, Jan 03 2012

Keywords

Comments

Each term divides its successor, as in A203483.
See A093883 for a guide to related sequences.

Crossrefs

Programs

  • Magma
    [(&*[(&*[Factorial(j) + Factorial(k): k in [1..j]])/(2*Factorial(j)): j in [1..n]]): n in [1..20]]; // G. C. Greubel, Aug 29 2023
    
  • Maple
    a:= n-> mul(mul(i!+j!, i=1..j-1), j=2..n):
    seq(a(n), n=1..10);  # Alois P. Heinz, Jul 23 2017
  • Mathematica
    (* First program *)
    f[j_]:= j!; z = 10;
    v[n_]:= Product[Product[f[k] + f[j], {j, k-1}], {k, 2, n}]
    d[n_]:= Product[(i-1)!, {i, n}]  (* A000178 *)
    Table[v[n], {n, z}]              (* A203482 *)
    Table[v[n+1]/v[n], {n, z-1}]     (* A203483 *)
    Table[v[n]/d[n], {n, 10}]        (* A203510 *)
    (* Second program *)
    Table[Product[j!+k!, {j,n}, {k,j-1}], {n,15}] (* G. C. Greubel, Aug 29 2023 *)
  • SageMath
    [product(product(factorial(j) + factorial(k) for k in range(1,j)) for j in range(1,n+1)) for n in range(1,16)] # G. C. Greubel, Aug 29 2023

Formula

a(n) ~ c * n^(n^3/3 + n^2/4 - 7*n/12 + 5/8) * (2*Pi)^(n*(n-1)/4) / exp(4*n^3/9 - n^2/8 - n), where c = 0.488888619502150098591650327163991582267254151817880403495924251381414248582... - Vaclav Kotesovec, Nov 20 2023

Extensions

Name edited by Alois P. Heinz, Jul 23 2017

A203483 a(n) = v(n+1)/v(n), where v = A203482.

Original entry on oeis.org

3, 56, 19500, 267841728, 236189890379520, 19303349192505048268800, 199126474924007956512865886208000, 339543987407937097660189431863908761600000000, 121553118121801544803671246298148699436481551316864204800000
Offset: 1

Views

Author

Clark Kimberling, Jan 03 2012

Keywords

Crossrefs

Programs

  • Magma
    [(&*[Factorial(k) + Factorial(n+1): k in [1..n]]): n in [1..16]]; // G. C. Greubel, Aug 29 2023
    
  • Mathematica
    (* First program *)
    f[j_]:= j!; z = 10;
    v[n_]:= Product[Product[f[k] + f[j], {j,k-1}], {k,2,n}]
    d[n_]:= Product[(i-1)!, {i, n}]   (* A000178 *)
    Table[v[n], {n,z}]                (* A203482 *)
    Table[v[n+1]/v[n], {n,z-1}]       (* this sequence *)
    Table[v[n]/d[n], {n,10}]          (* A203510 *)
    (* Second program *)
    Table[Product[k!+(n+1)!, {k,n}], {n,15}] (* G. C. Greubel, Aug 29 2023 *)
  • SageMath
    [product(factorial(k) + factorial(n+1) for k in range(1,n+1)) for n in range(1,16)] # G. C. Greubel, Aug 29 2023

Formula

a(n) = Product_{k=1..n} (k! + (n+1)!). - G. C. Greubel, Aug 29 2023
From Vaclav Kotesovec, Nov 20 2023: (Start)
a(n) ~ (n+1)!^n.
a(n) ~ (2*Pi)^(n/2) * n^(n^2 + 3*n/2) / exp(n^2 - 13/12). (End)
Showing 1-2 of 2 results.