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

1,1

Links

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

Example

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

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 *)

Prog

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

Crossrefs

Cf. A153766, A153767, A153762.

Sequence in context: A059337 A126240 A124110 * A371106 A371054 A360181

Adjacent sequences: A153765 A153766 A153767 * A153769 A153770 A153771

Keyword

nonn,easy

Author

Vincenzo Librandi, Jan 01 2009

Extensions

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

Status

approved