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.

A163212 Wilson quotients (A007619) which are primes.

Original entry on oeis.org

5, 103, 329891, 10513391193507374500051862069
Offset: 1

Views

Author

Peter Luschny, Jul 24 2009

Keywords

Comments

a(5) = A007619(137), a(6) = A007619(216), a(7) = A007619(381).
Same as A122696 without its initial term 2. - Jonathan Sondow, May 19 2013

Examples

			The quotient (720+1)/7 = 103 is a Wilson quotient and a prime, so 103 is a member.
		

Crossrefs

Programs

  • Maple
    # WQ defined in A163210.
    A163212 := n -> select(isprime,WQ(factorial,p->1,n)):
  • Mathematica
    Select[Table[p = Prime[n]; ((p-1)!+1)/p, {n, 1, 15}], PrimeQ] (* Jean-François Alcover, Jun 28 2013 *)
  • PARI
    forprime(p=2, 1e4, a=((p-1)!+1)/p; if(ispseudoprime(a), print1(a, ", "))) \\ Felix Fröhlich, Aug 03 2014

Formula

a(n) = A122696(n+1) = A007619(A225906(n)) = ((A050299(n+1)-1)!+1)/A050299(n+1). - Jonathan Sondow, May 19 2013