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

1, 17, 145, 427, 4327, 14195

Offset: 1

Author

Vincenzo Librandi, Sep 07 2012

Keywords

• nonn
• hard
• more

Comments

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

Crossrefs

Cf. A100357, A215434-A215446, A216375.

Programs

Mathematica

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

PARI

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

Extensions

a(6) from Robert Price, Mar 25 2014