login
A239788
Numbers n such that 3n^3 +/- 1 are twin primes.
1
4, 10, 14, 36, 54, 64, 70, 86, 150, 174, 176, 180, 200, 306, 384, 440, 494, 650, 706, 800, 824, 924, 976, 980, 986, 1020, 1026, 1054, 1360, 1464, 1504, 1506, 1536, 1564, 1604, 1680, 1724, 1736, 2066, 2076, 2116, 2134, 2136, 2166, 2200, 2220, 2314, 2380, 2456
OFFSET
1,1
COMMENTS
Numbers in this sequence are all even.
LINKS
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
Sequence in context: A125302 A365679 A175588 * A136862 A191635 A123925
KEYWORD
nonn,easy
AUTHOR
Derek Orr, Mar 26 2014
STATUS
approved