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.

Showing 1-2 of 2 results.

A336810 Continued fraction expansion of Sum_{k>=0} 1/(k!)!.

Original entry on oeis.org

2, 1, 1, 179, 2, 1196852626800230399, 1, 1, 179, 1, 1
Offset: 0

Views

Author

Daniel Hoyt, Nov 20 2020

Keywords

Comments

a(11), a(21), and a(41) have 152, 1349, and 12981 digits, respectively.

Crossrefs

Cf. A336686 (decimal expansion).

Programs

  • Mathematica
    ContinuedFraction[Sum[1/(k!)!, {k, 0, 6}], 21] (* Amiram Eldar, Nov 22 2020 *)
  • PARI
    contfrac(suminf(k=0, 1/(k!)!))

Formula

The peak terms have the form ((k+1)!)! / ((k!)!)^2 - 1. - Georg Fischer, Oct 19 2022 [pers. comm. with J. Shallit]
Let P(k) = ((k+1)!)! / ((k!)!)^2 - 1. After the first term, the rest of the sequence is an interleaving between the n-th runs of '1, 1' and '2' in A157196, and P(A001511(n)+1). - Daniel Hoyt, Jun 26 2023

A363842 Decimal expansion of Sum_{k>=0} 1/(k!)!^2.

Original entry on oeis.org

2, 2, 5, 0, 0, 0, 1, 9, 2, 9, 0, 1, 2, 3, 4, 5, 6, 7, 9, 0, 1, 2, 3, 4, 5, 6, 7, 9, 0, 1, 2, 3, 4, 5, 6, 7, 9, 0, 1, 2, 3, 4, 5, 6, 7, 9, 0, 1, 4, 9, 4, 3, 3, 7, 7, 0, 1, 0, 4, 2, 8, 4, 9, 4, 1, 6, 2, 2, 0, 3, 5, 2, 4, 4, 3, 4, 4, 8, 0, 7, 7, 5, 8, 5, 2, 2, 5
Offset: 1

Views

Author

Daniel Hoyt, Jun 23 2023

Keywords

Comments

1166401/518400 approximates this constant to 48 significant digits.

Examples

			2.25000192901234567901234567901234567901234567901...
		

Crossrefs

Cf. A363841 (continued fraction).
Cf. A336686.

Programs

  • Mathematica
    RealDigits[Sum[1/(k!)!^2, {k, 0, 4}], 10, 100][[1]]
  • PARI
    suminf(k=0, 1/k!!^2)
Showing 1-2 of 2 results.