A175236 Primes p such that 2^p+23 is also prime.

3, 7, 79, 359, 1031, 1039, 11311, 47599

Offset

1,1

Comments

a(9) > 5*10^5. - Robert Price, Sep 18 2015

Links

Table of n, a(n) for n=1..8.

Formula

A057203 INTERSECT A000040. [R. J. Mathar, Jul 06 2010]

Example

For p=3, 2^3+23=31; p=7, 2^7+23=131; p=79, 2^79+23=604462909807314587353111

Mathematica

Select[Prime[Range[1000]], PrimeQ[2^#+23]&] (*Robert Price, Sep 18 2015 *)

Prog

(Magma) [p: p in PrimesUpTo(1000) | IsPrime(2^p+23) ]

Crossrefs

Sequence in context: A181554 A116294 A077793 * A343763 A045974 A001531

Adjacent sequences: A175233 A175234 A175235 * A175237 A175238 A175239

Keyword

nonn

Author

Vincenzo Librandi, Mar 09 2010

Extensions

Two more terms from R. J. Mathar, Jul 06 2010

a(7)-a(8) from Robert Price, Sep 18 2015

Status

approved