OFFSET
1,2
COMMENTS
All the numbers in this sequence, excluding a(1), are even.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
EXAMPLE
3*2^3 - 1 = 23 is prime. Thus, 2 is a member of this sequence.
MATHEMATICA
Select[Range[1000], PrimeQ[3 #^3 - 1] &] (* Vincenzo Librandi, Mar 29 2014 *)
PROG
(Python)
import sympy
from sympy import isprime
{print(n) for n in range(10**3) if isprime(3*(n**3)-1)}
(PARI) s=[]; for(n=1, 1000, if(isprime(3*n^3-1), s=concat(s, n))); s \\ Colin Barker, Mar 27 2014
(Magma) [n: n in [0..1000] | IsPrime(3*n^3-1)]; // Vincenzo Librandi, Mar 29 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Derek Orr, Mar 26 2014
STATUS
approved