A075898 Numbers k such that 3^k + k^2 is prime.

2, 4, 10, 22, 40, 304, 1582, 3602, 46162, 127990

Offset: 1

Author

Zak Seidov, Oct 17 2002

Keywords

• nonn
• more

Comments

a(9) > 20000. - Jon E. Schoenfield, Jan 14 2015

a(10) > 10^5. - Lucas A. Brown, Feb 11 2021

Links

• Lucas A. Brown, A075898.py

Crossrefs

Cf. A075899 (for the corresponding primes).

Programs

Magma

[n: n in [0..1000] | IsPrime(3^n+n^2)]; // Vincenzo Librandi, Dec 16 2010

Mathematica

Select[Range[10000], PrimeQ[3^# + #^2] &] (* Vincenzo Librandi, Oct 04 2012 *)

PARI

is(n)=ispseudoprime(3^n+n^2) \\ Charles R Greathouse IV, Jun 12 2017

Extensions

a(6) from Vincenzo Librandi, Dec 16 2010

a(7) from D. S. McNeil, Dec 16 2010

a(8) from Vincenzo Librandi, Oct 04 2012

a(9) from Lucas A. Brown, Feb 11 2021

a(10) from Michael S. Branicky, Sep 07 2024