OFFSET
1,1
COMMENTS
The sequence of corresponding k starts: 1, 3, 9, 39, 165 (A180741).
Primes in A155603. - Altug Alkan, Oct 01 2016
FORMULA
MATHEMATICA
Select[Table[5^k + 3^k - 1, {k, 0, 200}], PrimeQ] (* Amiram Eldar, Aug 11 2024 *)
PROG
(PARI) lista(kmax) = {my(p); for(k = 0, kmax, p = 5^k + 3^k - 1; if(isprime(p), print1(p, ", "))); } \\ Amiram Eldar, Aug 11 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Sep 30 2016
STATUS
approved