OFFSET
1,2
COMMENTS
For s = 5, 8, 11, 14, 17, 20, ..., n_s = 1 + n + n^s is always composite for any n > 1. Also at n = 1, n_s = 3 is a prime for any s. So it is interesting to consider only the cases of s =/= 5, 8, 11, 14, 17, 20, ... and n > 1. Here we consider the case s = 16 and find several first n's making n_s a prime (or a probable prime).
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
EXAMPLE
2 is in the sequence because 1 + 2 + 2^16 = 65539 is prime.
MAPLE
A075715:=n->if type(1+n+n^16, prime) then n; fi; seq(A075715(n), n=1..3000); # Wesley Ivan Hurt, Dec 17 2013
MATHEMATICA
Select[Range[3000], PrimeQ[#^16 + # + 1] &] (* Vincenzo Librandi, Dec 17 2013 *)
PROG
(PARI) for(n=1, 3000, if(isprime(1+n+n^16), print1(n", ")))
(Magma) [n: n in [1..3000]| IsPrime(n^16+n+1)]; // Vincenzo Librandi, Dec 17 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Zak Seidov, Oct 03 2002
EXTENSIONS
More terms from Ralf Stephan, Mar 19 2003
STATUS
approved