A173092 Numbers k such that 3k-4, 3k-2, 3k+2, and 3k+4 are primes.

3, 5, 35, 65, 275, 495, 625, 695, 1085, 1155, 1885, 3145, 4335, 5215, 5245, 5355, 6015, 6305, 6475, 7005, 7425, 8435, 10575, 11615, 14595, 17115, 18445, 20995, 22405, 23165, 24075, 25755, 26565, 27015, 27575, 29605, 32615, 33045, 33705, 36615, 38845, 39765, 40735, 45155, 48055, 52425

Offset

1,1

Links

Table of n, a(n) for n=1..46.

Formula

a(n) = A173037(n)/3.

Example

3 is a term because 3*3-4=5, 3*3-2=7, 3*3+2=11, and 3*3+4=13 are all prime.

Mathematica

Select[Range[10^5], PrimeQ[3# - 4]&&PrimeQ[3# - 2] && PrimeQ[3# + 2] && PrimeQ[3# + 4]&] (* Alonso del Arte, Dec 04 2010 *)

Prog

(Magma) [ n: n in [0..60000] | IsPrime(3*n-2) and IsPrime(3*n+2) and IsPrime(3*n-4) and IsPrime(3*n+4) ]; // Vincenzo Librandi, Dec 04 2010

Crossrefs

Cf. A173037.

Sequence in context: A052468 A055786 A001790 * A057908 A120828 A077784

Adjacent sequences: A173089 A173090 A173091 * A173093 A173094 A173095

Keyword

nonn,less

Author

Juri-Stepan Gerasimov, Feb 10 2010, Feb 19 2010

Extensions

Entries checked by D. S. McNeil, Nov 26 2010

Extended by Vincenzo Librandi and Charles R Greathouse IV, Mar 25 2010

Status

approved