A153503 Primes p such that 2^(p-1)+3 is prime.

2, 3, 5, 7, 13, 17, 19, 29, 31, 229, 2371, 4003, 33029, 55457, 58313, 205963

Offset

1,1

Comments

A prime p is in the sequence if and only if p-1 is in A057732.

Links

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

Example

For p = 2, 2^(p-1)+3 = 5 is prime;
for p = 17, 2^(p-1)+3 = 65539 is prime;
for p = 31, 2^(p-1)+3 = 1073741827 is prime.

Mathematica

Select[Prime[Range[3000]], PrimeQ[2^(# - 1) + 3] &] (* Vincenzo Librandi, Jun 09 2015

Prog

[p: p in PrimesUpTo(2000) | IsPrime(2^(p-1) + 3)]; // Vincenzo Librandi, Jun 09 2015

Crossrefs

Cf. A057732 (numbers n such that 2^n + 3 is prime), A057736 (primes p such that 2^p + 3 is prime), A000043 (primes p such that 2^p - 1 is prime).

Sequence in context: A134207 A133244 A077040 * A049587 A293008 A038903

Adjacent sequences: A153500 A153501 A153502 * A153504 A153505 A153506

Keyword

nonn,more

Author

Vincenzo Librandi, Dec 28 2008

Extensions

Edited and a(13)-a(15) (based on A057732) added by Klaus Brockhaus, Jan 06 2009

a(16) by Vincenzo Librandi, Jun 09 2015

Status

approved