OFFSET
1,1
COMMENTS
These numbers are a subset of Generalized Fermat Primes power 8.
All numbers from 1 to 235763 has been checked by LLR, no other primes found.
k is not congruent to 6 mod 25 because otherwise (13*2^k)^8+1 would be divisible by 401. - Bruno Berselli, Sep 21 2018
LINKS
Chris K. Caldwell, The Prime Database: 815730721*2^1882432+1
EXAMPLE
4 is a term because (13*2^4)^8+1 = 3503536769037500417 is a prime number.
MATHEMATICA
Select[Range[700], PrimeQ[(13 2^#)^8 + 1] &] (* Vincenzo Librandi, Sep 21 2018 *)
PROG
(Magma) [n: n in [1..700] | IsPrime((13*2^n)^8+1)]; // Vincenzo Librandi, Sep 21 2018
(PARI) isok(k) = ispseudoprime((13*2^k)^8+1); \\ Altug Alkan, Sep 21 2018
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Lei Zhou, Sep 13 2018
STATUS
approved