A058046 Numbers n such that 5^n - n is prime.

2, 6, 12, 362, 884, 9722

Offset

1,1

Comments

Farideh Firoozbakht reports that the only known prime of the form 5^n + n occurs when n = 7954 and that there are no others up to 20200. Oct 11 2003.

a(7) > 2*10^5. - Robert Price, Jan 16 2014

Links

Table of n, a(n) for n=1..6.

Mathematica

Do[ If[ PrimeQ[ 5^n - n ], Print[ n ] ], {n, 1, 13400} ]

Prog

(PARI) is(n)=ispseudoprime(5^n-n) \\ Charles R Greathouse IV, Feb 20 2017

Crossrefs

Sequence in context: A132076 A309743 A291062 * A298410 A367314 A328448

Adjacent sequences: A058043 A058044 A058045 * A058047 A058048 A058049

Keyword

nonn

Author

Robert G. Wilson v, Nov 17 2000

Extensions

The sixth term was found by Farideh Firoozbakht, who reports that there are no others up to 13400, Oct 11 2003

Status

approved