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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A072694 (p(n)#)^p(n), or n-th primorial raised to n-th prime power.

Original entry on oeis.org

4, 216, 24300000, 18010885410000000, 9993825885714653185036703100000000000, 16151740133123735772971793020980457559217933230000000000000
Offset: 1

Views

Author

Rick L. Shepherd, Jul 03 2002

Keywords

Comments

a(7) through a(10) have 98, 133, 193 and 285 digits, respectively.

Examples

			a(3) = 24300000 because (p(3)#)^p(3) = (5*3*2)^5 = 30^5 = 24300000.
		

Crossrefs

Cf. A002110 (primorials), A068210 ((p(n)!)^p(n)).

Programs

  • Mathematica
    With[{nn=6},First[#]^Last[#]&/@Thread[{Rest[FoldList[Times, 1, Prime[ Range[nn]]]],Prime[Range[nn]]}]] (* Harvey P. Dale, Mar 16 2012 *)
  • PARI
    for(n=1,6,print1((prod(k=1,n, prime(k)))^prime(n),","))

Formula

a(n) = (p(n)#)^p(n), where p(n) is n-th prime and # denotes primorial (A002110).

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 1-2 of 2 results.