A038869 Primes p such that both p-2 and 2p-1 are prime.

7, 19, 31, 139, 199, 229, 271, 601, 619, 661, 811, 829, 1279, 1429, 1609, 2029, 2089, 2131, 2311, 2551, 2791, 3169, 3331, 3391, 3529, 3769, 4051, 4159, 4231, 4261, 4339, 4639, 4801, 5419, 5479, 5659, 5851, 6271, 6301, 6361, 6691, 6961, 7561, 7951, 8539

Offset

1,1

Comments

Primes p such that A(2*p) - 3*A(p) = 3 (7, 31, 661, 811, 2551, ...) and primes p such that 7*A(p) - A(2*p) = 21 (19, 139, 619, 1429, ...), where A=A288814, are both subsequences of A038869. - David James Sycamore, Aug 07 2017

Links

Harvey P. Dale, Table of n, a(n) for n = 1..10000

Mathematica

Transpose[Select[Partition[Prime[Range[1200]], 2, 1], #[[2]]-#[[1]]==2 && PrimeQ[2#[[2]]-1]&]][[2]] (* Harvey P. Dale, Jun 19 2014 *)

Prog

(Magma)[n: n in [0..10000]|IsPrime(n) and IsPrime(n-2) and IsPrime(2*n-1)] // Vincenzo Librandi, Dec 18 2010
(PARI) is(n)=n%6==1 && isprime(n-2) && isprime(n) && isprime(2*n-1) \\ Charles R Greathouse IV, Aug 09 2017

Crossrefs

Cf. A005382.

Sequence in context: A145042 A153892 A338410 * A147503 A147465 A053591

Adjacent sequences: A038866 A038867 A038868 * A038870 A038871 A038872

Keyword

nonn

Author

Thomas Kellar

Status

approved