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

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

Offset

1,2

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

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

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

Mathematica

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

Prog

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

Crossrefs

Sequence in context: A216260 A160577 A256603 * A350397 A247344 A220601

Adjacent sequences: A058825 A058826 A058827 * A058829 A058830 A058831

Keyword

nonn

Author

Robert G. Wilson v, Jan 04 2001

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

Status

approved