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

Author

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

Keywords

• nonn
• less

Examples

			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.
		

Crossrefs

Cf. A173037.

Programs

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

Mathematica

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

Formula

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

Extensions

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

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