A102870 Primes of the form 3^k + 8.

11, 17, 89, 251, 6569, 1594331, 4782977, 3486784409, 1350851717672992097, 984770902183611232889, 5474401089420219382077155933569751771, 969773729787523602876821942164080815560169

Offset: 1

Author

Roger L. Bagula, Mar 01 2005

Keywords

• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..16

Crossrefs

Cf. A000040, A217136 (corresponding k's).

Programs

Magma

[ a: n in [0..100] | IsPrime(a) where a is 3^n+8 ]; // Vincenzo Librandi, Jul 19 2012

Mathematica

a = Delete[Union[Flatten[Table[If [PrimeQ[3^n + 8] == True, 3^n + 8, 0], {n, 1, 200}]]], 1]
Select[Table[3^n+8,{n,0,200}],PrimeQ] (* Vincenzo Librandi, Jul 19 2012 *)

Formula

a(n) = 3^A217136(n) + 8. - Elmo R. Oliveira, Nov 09 2023