A124098 Primes p such that 3p -+ 4 are primes.

3, 5, 11, 19, 31, 59, 79, 89, 131, 151, 191, 199, 229, 241, 311, 389, 409, 431, 509, 521, 541, 661, 719, 739, 821, 971, 1109, 1151, 1181, 1451, 1549, 1669, 1759, 1801, 1949, 1951, 2011, 2039, 2069, 2089, 2111, 2131, 2341, 2411, 2671, 2699, 2791, 3001, 3181

Offset: 1

Author

Zak Seidov, Nov 26 2006

Keywords

• nonn

Crossrefs

Cf. A125215, A125216, A125272.

Programs

Magma

[p: p in PrimesUpTo(70000)| IsPrime(3*p-4)and IsPrime(3*p+4)] // Vincenzo Librandi, Jan 29 2011

Mathematica

lst={}; Do[p=Prime[n]; If[PrimeQ[3*p-4]&&PrimeQ[3*p+4],AppendTo[lst,p]],{n,7!}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 16 2009 *)
Select[Prime[Range[500]],AllTrue[3#+{4,-4},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Oct 02 2015 *)

Formula

a(n)= A125216(n)/3.