A172996 Primes of form (3^n+7)/2.

5, 17, 1097, 304133393856678854559841996309430657

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..7

Formula

a(n) = (3^A172995(n)+7)/2.

Mathematica

Select[Table[(3^n + 7)/2, {n, 500}], PrimeQ] (* Vincenzo Librandi, Sep 24 2015 *)

Prog

(Magma) [a: n in [0..500] | IsPrime(a) where a is (3^n+7) div 2]; // Vincenzo Librandi, Sep 24 2015
(PARI) for(n=1, 1e3, if(isprime(k=(3^n+7)/2), print1(k", "))) \\  Altug Alkan Sep 24 2015

Crossrefs

Cf. A172995.

Sequence in context: A218378 A119531 A248921 * A253624 A085832 A062223

Adjacent sequences: A172993 A172994 A172995 * A172997 A172998 A172999

Keyword

nonn

Author

Vincenzo Librandi, Feb 07 2010

Status

approved