A058829 Numbers k such that 6^k - k is prime.

1, 19, 43, 607, 889, 3727, 12229, 124433, 246229

Offset

1,2

Comments

a(8) > 30000. - Giovanni Resta, Apr 07 2013

a(9) > 2*10^5. - Robert Price, Jan 21 2014

Links

Table of n, a(n) for n=1..9.

Mathematica

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

Prog

(PARI) is(n)=ispseudoprime(6^n-n) \\ Charles R Greathouse IV, Feb 20 2017

Crossrefs

Cf. A024063 (6^n-n).

Sequence in context: A185167 A140619 A229765 * A063313 A044096 A044477

Adjacent sequences: A058826 A058827 A058828 * A058830 A058831 A058832

Keyword

nonn,hard,more

Author

Robert G. Wilson v, Jan 04 2001

Extensions

a(6) from Vincenzo Librandi, Sep 29 2012

a(7) from Giovanni Resta, Apr 07 2013

a(8) from Robert Price, Jan 21 2014

a(9) from Ryan Propper, Dec 11 2022

Status

approved