OFFSET
1,2
COMMENTS
a(55) > 5*10^5. - Robert Price, Sep 14 2015
For these numbers k, 2^(k-1)*(2^k+15) has deficiency 16 (see A125248). - M. F. Hasler, Jul 18 2016
LINKS
Henri Lifchitz and Renaud Lifchitz (Editors), Search for 2^n+15, PRP Top Records.
EXAMPLE
For k = 5, 2^5 + 15 = 47 is prime.
For k = 15, 2^15 + 15 = 32783 is prime.
MATHEMATICA
Do[ If[ PrimeQ[ 2^n + 15 ], Print[n]], { n, 1, 12422 }]
Select[Range[15000], PrimeQ[2^# + 15] &] (* Vincenzo Librandi, Aug 28 2015 *)
PROG
(Magma) [n: n in [0..1500] | IsPrime(2^n+15)]; // Vincenzo Librandi, Aug 28 2015
(PARI) for(n=1, 9e9, ispseudoprime(2^n+15)&&print1(n", ")) \\ M. F. Hasler, Jul 18 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Sep 15 2000
EXTENSIONS
a(45)-a(53) from Robert Price, Dec 06 2013
a(54) from Robert Price, Sep 14 2015
a(55) from Stefano Morozzi, added by Elmo R. Oliveira, Dec 11 2023
STATUS
approved