cp's OEIS Frontend

A285983 Prime numbers p such that 3*p has distance <= 2 from the nearest twin prime number.

%I A285983 #12 May 12 2017 13:39:58
%S A285983 2,3,5,7,11,13,19,23,37,47,59,61,67,79,89,103,139,173,191,199,269,271,
%T A285983 277,293,349,353,383,409,431,433,439,541,557,643,677,709,757,769,863,
%U A285983 887,911,929,991,1039,1087,1109,1123,1129,1153,1181,1187
%N A285983 Prime numbers p such that 3*p has distance <= 2 from the nearest twin prime number.
%C A285983 Also prime numbers distance <= 1 from an element of A167379. - _Danny Rorabaugh_, May 04 2017
%t A285983 fQ[n_] := (PrimeQ[3n -4] && PrimeQ[3n -2]) || (PrimeQ[3n +2] && PrimeQ[3n +4]); Join[{2}, Select[ Prime@ Range@ 200, fQ]] (* _Robert G. Wilson v_, Apr 30 2017 *)
%o A285983 (PARI) {
%o A285983 print1(2", ");
%o A285983 forprime(n=3,1000,
%o A285983          p3=3*n;
%o A285983          if((isprime(p3+2)&&isprime(p3+4))||(isprime(p3-2)&&isprime(p3-4)),
%o A285983              print1(n", ")
%o A285983            )
%o A285983         )
%o A285983 }
%Y A285983 Cf. A001359, A006512, A060212.
%K A285983 nonn
%O A285983 1,1
%A A285983 _Dimitris Valianatos_, Apr 29 2017