A034924 Numbers k such that 47^k-46 is prime.

5, 11, 13, 53, 115, 899, 2287

Offset

1,1

Comments

Related to hyperperfect numbers of a certain form.

Links

Table of n, a(n) for n=1..7.

J. S. McCranie, A study of hyperperfect numbers, J. Int. Seqs. Vol. 3 (2000) #P00.1.3.

Mathematica

Select[Range[2000], PrimeQ[47^# - 46] &] (* Vincenzo Librandi, Sep 26 2012 *)

Prog

(PARI) is(n)=ispseudoprime(47^n-46) \\ Charles R Greathouse IV, Jun 13 2017
(Python)
from sympy import isprime
def afind(limit, startat=1):
  pow47 = 47**startat
  for k in range(startat, limit+1):
    if isprime(pow47 - 46): print(k, end=", ")
    pow47 *= 47
afind(900) # Michael S. Branicky, May 11 2021

Crossrefs

Sequence in context: A116440 A098720 A115091 * A018607 A032481 A365502

Adjacent sequences: A034921 A034922 A034923 * A034925 A034926 A034927

Keyword

nonn,more

Author

Jud McCranie

Extensions

a(6) from Vincenzo Librandi, Sep 26 2012

a(7) from Michael S. Branicky, May 11 2021

Status

approved