A162715 Primes of the form 3^p-2^(p+1), where p is also a prime.

11, 179, 1931, 617669101316651, 14130386090585813000157964091, 19088056323407826758511836230558252318494847619

Offset: 1

Author

Vincenzo Librandi, Jul 11 2009

Keywords

• nonn

Comments

The next term has 1117 digits and is not included explicitly for that reason.

Crossrefs

Cf. A162714.

Programs

Magma

[a: p in PrimesInInterval(3,1200) | IsPrime(a) where a is 3^p - 2^(p + 1)]; // Vincenzo Librandi, Sep 11 2013

Mathematica

Select[Table[3^p - 2^(p + 1), {p, Prime[Range[70]]}], PrimeQ] (* Vincenzo Librandi, Sep 11 2013 *)

Formula

a(n) = 3^A162714(n)-2^(1+A162714(n)) .

Extensions

Clarified status of p in the definition - R. J. Mathar, Oct 16 2009