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 1-5 of 5 results.

A039716 a(n) = prime(n)!.

Original entry on oeis.org

2, 6, 120, 5040, 39916800, 6227020800, 355687428096000, 121645100408832000, 25852016738884976640000, 8841761993739701954543616000000, 8222838654177922817725562880000000, 13763753091226345046315979581580902400000000, 33452526613163807108170062053440751665152000000000
Offset: 1

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Author

Keywords

Comments

Subsequence of A000142.

Crossrefs

Programs

Formula

a(n) = A000142(A000040(n)).
a(n) = A177946(n)*A000142(n). - Reinhard Zumkeller, May 15 2010
Sum_{n>=1} 1/a(n) = A100124. - Amiram Eldar, Nov 13 2020

A100127 Decimal expansion of Sum_{n>0} prime(n)/n!.

Original entry on oeis.org

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

Views

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Nov 11 2004

Keywords

Comments

This constant is irrational (Erdős, 1958). - Amiram Eldar, Apr 13 2020

Examples

			4.73863870268621999271779470348124955360182384664210664248096193484375408779697167489...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[ Sum[ Prime[n]/n!, {n, 75}], 10, 105][[1]] (* Robert G. Wilson v, Jan 18 2015 *)
  • PARI
    default(realprecision,100);sum(n=1,100,prime(n)/(n!),0.)

A100126 Decimal expansion of Sum_{n>0} n/(prime(n)!).

Original entry on oeis.org

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

Views

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Nov 11 2004

Keywords

Examples

			0.8591271103510884303682282623075379082585345770617761756616761775868373279803735889751322022482625639...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[Total[Table[n/Prime[n]!,{n,20}]],10,120][[1]] (* Harvey P. Dale, Oct 26 2015 *)
  • PARI
    default(realprecision,100);sum(n=1,100,n/(prime(n)!),0.)

A100128 Decimal expansion of Sum_{n>0} 1/(n*prime(n)^n).

Original entry on oeis.org

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

Views

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Nov 11 2004

Keywords

Examples

			0.5583276222317691586142791968036046951752521282087420173902229174235854763316376176520093696726521040...
		

Crossrefs

Programs

  • PARI
    suminf(k=1, 1/(k*prime(k)^k))

A370697 Decimal expansion of Sum_{p prime} 1/p!^p.

Original entry on oeis.org

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

Views

Author

Roberto Trocchi, Jun 07 2024

Keywords

Examples

			0.25462962966981738683127573227020697042409997891314217843798476619...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[Sum[1/Prime[n]!^Prime[n], {n, 1, 12}], 10, 1000] // First
  • PARI
    suminf(k=1,1/prime(k)!^prime(k)) \\ Hugo Pfoertner, Jun 22 2024
Showing 1-5 of 5 results.