A153768 Numbers n such that n, 8n-9 and 8n+9 are primes.

11, 29, 31, 109, 199, 251, 269, 379, 419, 521, 599, 601, 661, 881, 991, 1091, 1231, 1289, 1789, 1831, 1861, 1901, 1949, 2239, 2689, 2969, 3181, 3251, 3301, 3359, 3499, 3779, 3821, 4099, 4201, 4339, 4561, 4651, 4679, 4789, 4871, 5281, 5471, 5641, 5659

Offset: 1

Author

Vincenzo Librandi, Jan 01 2009

Keywords

• nonn
• easy

Examples

			For n=11, even 8n-9=79 and 8n+9=97 are primes, therefore 11 is in the sequence.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A153766, A153767, A153762.

Programs

Magma

[p: p in PrimesUpTo(6000) | IsPrime(8*p-9) and IsPrime(8*p+9)]; // Vincenzo Librandi, Apr 05 2013

Mathematica

lst={}; Do[p=Prime[n]; If[PrimeQ[8*p-9]&&PrimeQ[8*p+9],AppendTo[lst,p]],{n,7!}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 16 2009 *)
Select[Prime[Range[6000]], PrimeQ[8 # - 9] && PrimeQ[8 # + 9] &] (* Vincenzo Librandi, Apr 05 2013 *)
Select[Prime[Range[800]],AllTrue[8#+{9,-9},PrimeQ]&] (* Harvey P. Dale, Apr 05 2023 *)

Extensions

241 replaced by 251 and extended by R. J. Mathar, Jan 07 2009