OFFSET
1,1
COMMENTS
Main entry for this sequence is A001775.
Also primes of the form 38 * 4^n - 1, since even-numbered exponents yield numbers divisible by three.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..20
MATHEMATICA
Select[19*2^Range[140]-1, PrimeQ] (* Harvey P. Dale, Mar 07 2014 *)
PROG
(Magma) [a: n in [0..250] | IsPrime(a) where a is (19 * 2^n - 1)]; // Vincenzo Librandi, Mar 08 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Kevin Batista (kevin762401(AT)yahoo.com), Jun 16 2010
EXTENSIONS
Edited by Charles R Greathouse IV, Aug 29 2010
Edited by Charles R Greathouse IV, Sep 02 2010
More terms from Harvey P. Dale, Mar 07 2014
STATUS
approved