OFFSET
1,1
COMMENTS
Numbers in this sequence are all even.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
EXAMPLE
3*4^3-1 = 191 is prime and 3*4^3+1 = 193 is prime. Thus, 4 is a member of this sequence.
MATHEMATICA
Select[Range[5000], PrimeQ[3 #^3 - 1] && PrimeQ[3 #^3 + 1]&] (* Vincenzo Librandi, Mar 29 2014 *)
PROG
(Python)
import sympy
from sympy import isprime
{print(n) for n in range(10**4) if isprime(3*(n**3)+1) and isprime(3*(n**3)-1)}
(PARI) s=[]; for(n=1, 3000, if(isprime(3*n^3-1) && isprime(3*n^3+1), s=concat(s, n))); s \\ Colin Barker, Mar 27 2014
(Magma) [n: n in [0..5000] | IsPrime(3*n^3-1) and IsPrime(3*n^3+1)]; // Vincenzo Librandi, Mar 29 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Derek Orr, Mar 26 2014
STATUS
approved