A045536 Primes p such that p+2 and 2p+1 are also prime.

3, 5, 11, 29, 41, 179, 191, 239, 281, 419, 431, 641, 659, 809, 1019, 1031, 1049, 1229, 1289, 1451, 1481, 1931, 2129, 2141, 2339, 2549, 2969, 3299, 3329, 3359, 3389, 3539, 3821, 3851, 4019, 4271, 4481, 5231, 5279, 5441, 5501, 5639, 5741, 5849, 6131

Offset: 1

Author

Thomas Kellar

Keywords

• nonn
• easy

Comments

Intersection of A001359 and A005384. - Zak Seidov, Feb 28 2017

Links

• T. D. Noe, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A001359, A005384.

Programs

Magma

[p: p in PrimesUpTo(6200) | IsPrime(p+2) and IsPrime(2*p+1)]; // Vincenzo Librandi, Apr 08 2013

Maple

select(t -> isprime(t) and isprime(t+2) and isprime(2*t+1), [3, seq(t,t=5..10000,6)]); # Robert Israel, Feb 28 2017

Mathematica

Select[Prime[Range[1000]], PrimeQ[#+2] && PrimeQ[2#+1]&] (* Vladimir Joseph Stephan Orlovsky, Mar 30 2011*)

PARI

is(n)=isprime(n) && isprime(n+2) && isprime(2*n+1) \\ Charles R Greathouse IV, Feb 25 2014

Extensions

Corrected by Jud McCranie, Dec 30 2000

Name changed and incorrect comment and program removed by T. D. Noe, Aug 05 2010