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.

A376057 a(n) is the denominator of the sum S(n) defined in A376056.

Original entry on oeis.org

1, 2, 14, 994, 6917246, 430634636937890, 2039908095836912108987531110990, 54095925512992695768212345567905438957243461489279855615252290
Offset: 0

Views

Author

N. J. A. Sloane, Sep 14 2024

Keywords

Examples

			The first few values of S(n) are 0/1, 1/2, 13/14, 993/994, 6917245/6917246, 430634636937889/430634636937890, ...
		

Crossrefs

Programs

  • Maple
    a:= proc(n) a(n):= `if`(n=0, 1, ((2*n-1)*a(n-1)+1)*a(n-1)) end:
    seq(a(n), n=0..7);  # Alois P. Heinz, Oct 18 2024
  • Mathematica
    RecurrenceTable[{a[n+1] == (2*n+1)*a[n]^2 + a[n], a[0] == 1}, a, {n, 0, 7}] (* Amiram Eldar, Sep 15 2024 *)

Formula

a(n+1) = (2*n+1)*a(n)^2 + a(n), with a(0) = 1.

Extensions

a(0)=1 prepended by Alois P. Heinz, Oct 18 2024