A104070 Primes of the form 2^k + 9.

11, 13, 17, 41, 73, 137, 521, 1033, 262153, 8388617, 1073741833, 137438953481, 140737488355337, 144115188075855881, 73786976294838206473, 4835703278458516698824713, 39614081257132168796771975177, 664613997892457936451903530140172297

Offset: 1

Author

Roger L. Bagula, Mar 02 2005

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..34

Crossrefs

Cf. A000040, A057196 (numbers k such that 2^k + 9 is prime). [From Klaus Brockhaus, Mar 14 2009]

Programs

Magma

[a: n in [0..250] | IsPrime(a) where a is 2^n+9]; // Vincenzo Librandi, Jan 26 2011

Mathematica

a = Delete[Union[Flatten[Table[If [PrimeQ[2^n + 9] == True, 2^ n + 9, 0], {n, 1, 400}]]], 1]
Select[2^Range[0,100]+9,PrimeQ] (* Harvey P. Dale, Mar 11 2023 *)

Formula

a(n) = 2^A057196(n) + 9. - Elmo R. Oliveira, Nov 08 2023