A058828 Numbers k such that 6^k + k is prime.

1, 305, 761, 1357, 3793, 4027, 85481

Offset: 1

Author

Robert G. Wilson v, Jan 04 2001

Keywords

• nonn

Comments

The next terms are > 12000. - Bruno Berselli, Sep 30 2012

a(8) exceeds 120,000 (from Mischa Rodermond). - Jeppe Stig Nielsen, Dec 05 2022

Links

• Henri Lifchitz and Renaud Lifchitz, PRP Top: Search for 6^k+k, finds a(7).

Programs

Mathematica

Do[ If[ PrimeQ[6^n + n], Print[n] ], {n, 2500} ]
Select[Range[0, 4000], PrimeQ[(6^# + #)] &] (* Vincenzo Librandi, Sep 29 2012 *)

PARI

is(n)=ispseudoprime(6^n+n) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(5) from Vincenzo Librandi, Sep 29 2012

a(6) from Bruno Berselli, Sep 29 2012

a(7) from Jeppe Stig Nielsen, Dec 05 2022