A158712 Primes p such that p1=Floor[p/2]+p is prime and p2=Ceiling[p1/2]+p1 is prime.

2, 5, 13, 101, 293, 421, 541, 661, 821, 1021, 1301, 1493, 2621, 3221, 3373, 3853, 5693, 5981, 6133, 6421, 6733, 7853, 8861, 8941, 9173, 9221, 9341, 9901, 10061, 10093, 10181, 10613, 15373, 16061, 16333, 16381, 16421, 17093, 18061, 18493, 19141

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Mar 24 2009

Keywords

• nonn

Crossrefs

Cf. A158708, A158709, A158710, A158711

Programs

Mathematica

lst={};Do[p=Prime[n];If[PrimeQ[p=Floor[p/2]+p],If[PrimeQ[p=Ceiling[p/2]+p],AppendTo[lst,Prime[n]]]],{n,7!}];lst
pQ[n_]:=Module[{p1=Floor[n/2]+n},AllTrue[{p1,Ceiling[p1/2]+p1},PrimeQ]]; Select[Prime[Range[2500]],pQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 07 2019 *)

Extensions

Definition corrected by Harvey P. Dale, Feb 07 2019