A216424 Numbers k such that 4^k + k^4 - 1 is prime.

2, 16, 74, 164, 518, 796, 8756, 12598

Offset: 1

Author

Vincenzo Librandi, Sep 07 2012

Keywords

• nonn

Comments

a(9) > 10^5. - Robert Price, Feb 04 2014

Crossrefs

Cf. A100357, A215434-A215437, A215439-A215446, A216375.

Programs

Magma

[n: n in [0..800] | IsPrime(4^n+n^4-1)];

Mathematica

Select[Range[0, 5000], PrimeQ[4^# + #^4 - 1] &]

PARI

is(n)=ispseudoprime(4^n+n^4-1) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(7)-a(8) from Robert Price, Feb 04 2014