A237811 Primes p such that 2*p+1 and 2*p+9 are also prime.

2, 5, 11, 29, 131, 179, 239, 281, 359, 491, 641, 659, 719, 761, 809, 911, 1229, 1439, 1481, 1811, 2549, 2699, 2819, 3299, 3449, 3491, 4211, 4349, 4481, 5051, 5279, 5441, 5639, 5741, 6101, 6269, 6449, 6581, 6899, 7121, 7211, 7541, 7649, 7691, 8111, 8741, 8951

Offset

1,1

Links

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

Example

11 is in the sequence because 11, 2*11+1 = 23 and 2*11+9 = 31 are all prime.

Mathematica

Select[Prime[Range[10000]], PrimeQ[2 # + 1]&&PrimeQ[2 # + 9]&] (* Vincenzo Librandi, Feb 15 2014 *)

Prog

(PARI) s=[]; forprime(p=2, 10000, if(isprime(2*p+1) && isprime(2*p+9), s=concat(s, p))); s
(Magma) [p: p in PrimesUpTo(9200) | IsPrime(2*p+1) and IsPrime(2*p+9)]; // Vincenzo Librandi, Feb 15 2014

Crossrefs

Cf. A126107, A237810, A237812, A237813, A237814.

Sequence in context: A014211 A160911 A092764 * A264771 A176637 A272675

Adjacent sequences: A237808 A237809 A237810 * A237812 A237813 A237814

Keyword

nonn,easy

Author

Colin Barker, Feb 13 2014

Status

approved