A068712 Primes of the form 5*2^k + 3.

13, 23, 43, 83, 163, 643, 1283, 10243, 20483, 1310723, 5242883, 335544323, 1342177283, 21474836483, 85899345923, 43980465111043, 87960930222083, 5629499534213123, 22517998136852483, 1441151880758558723

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..38

Example

1283 is a term as a concatenation of 2^7 and 3.

Mathematica

Select[5*2^Range[60]+3, PrimeQ]  (* Harvey P. Dale, Feb 04 2011 *)

Prog

(PARI) for(n=1, 150, if(isprime(2^n*5+3)==1, print1(2^n*5+3, ", ")))
(Magma) [a: n in [1..100] | IsPrime(a) where a is 5*2^n + 3]; // Vincenzo Librandi, Dec 08 2011

Crossrefs

Cf. A058586, A068715, A144487, A211486.

Sequence in context: A256177 A320752 A213665 * A103166 A154863 A194156

Adjacent sequences: A068709 A068710 A068711 * A068713 A068714 A068715

Keyword

nonn

Author

Amarnath Murthy, Mar 05 2002

Extensions

More terms from Benoit Cloitre, Mar 09 2002

Status

approved