A216422 Numbers k such that 19^k + k^19 - 1 is prime.

1, 17, 145, 427, 4327, 14195

Offset

1,2

Comments

a(7) > 10^5. - Robert Price, Mar 25 2014

Links

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

Mathematica

Select[Range[0, 5000], PrimeQ[19^# + #^19 - 1] &]

Prog

(PARI) is(n)=ispseudoprime(19^n+n^19-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A100357, A215434-A215446, A216375.

Sequence in context: A228254 A304207 A163038 * A008417 A241796 A181908

Adjacent sequences: A216419 A216420 A216421 * A216423 A216424 A216425

Keyword

nonn,hard,more

Author

Vincenzo Librandi, Sep 07 2012

Extensions

a(6) from Robert Price, Mar 25 2014

Status

approved