A259298 Numbers k such that k^2*2^k + 3 is prime.

0, 1, 2, 11, 22, 40, 79, 145, 152, 244, 271, 1471, 2516, 3460, 4130, 4550, 7534, 12973, 14051, 14176, 16093, 16952, 28565, 121319

Offset: 1

Author

Juri-Stepan Gerasimov, Jun 23 2015

Keywords

• nonn
• more

Comments

Primes: 3, 5, 19, 247811, 2030043139, 1759218604441603,...

Examples

			2 is in this sequence because 2^2*2^2 + 3 = 19 and 19 is prime.
		

Crossrefs

Cf. A058780.

Programs

Magma

[n: n in [0..1000] | IsPrime(n^2*2^n+3)];

Mathematica

Select[Range[0, 10000], PrimeQ[#^2 2^# + 3] &] (* Vincenzo Librandi, Jun 25 2015 *)

PARI

is(n)=ispseudoprime(n^2*2^n+3) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

More terms from Vincenzo Librandi, Jun 25 2015

a(18)-a(22) from Jinyuan Wang, May 15 2020

a(23) from Michael S. Branicky, Apr 20 2023

a(24) from Michael S. Branicky, Jul 23 2024