A125216 -id:A125216 - cp's OEIS frontend

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

Zak Seidov, Nov 26 2006

nonn

Cf. A125215, A125216, A125272.

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

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 *)

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

A176140 Semiprimes s such that both s + 3 and s - 3 are primes.

Original entry on oeis.org

10, 14, 26, 34, 86, 106, 134, 194, 226, 254, 274, 314, 334, 386, 446, 566, 974, 1094, 1126, 1226, 1234, 1286, 1294, 1486, 1546, 1874, 2066, 2374, 2386, 2554, 2854, 2906, 2966, 3086, 3166, 3254, 3326, 3466, 3694, 4054, 4286, 4594, 4786, 4874, 4934, 4954

Offset: 1

Vladimir Joseph Stephan Orlovsky, Apr 09 2010

nonn

2*5=10-+3->7,13 primes,...

Cf. A125215, A125216

f[n_]:=Last/@FactorInteger[n]=={1,1};lst={};Do[If[f[n]&&PrimeQ[n-3]&&PrimeQ[n+3],AppendTo[lst,n]],{n,0,4*7!}];lst
Select[Range[5000],PrimeOmega[#]==2&&AllTrue[#+{3,-3},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Nov 05 2017 *)

Definition corrected by Zak Seidov, May 06 2013

cp's OEIS Frontend

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

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