A139404 Numbers k such that 24*k + 5 and 24*k + 7 are twin primes.

0, 1, 4, 6, 8, 11, 19, 34, 44, 51, 53, 54, 78, 81, 83, 89, 93, 96, 99, 106, 116, 141, 144, 148, 149, 159, 163, 173, 176, 184, 188, 193, 209, 228, 229, 239, 258, 261, 279, 286, 306, 316, 323, 328, 331, 351, 358, 368, 369, 389, 393, 394, 401, 403, 418, 429, 446

Offset

1,3

Comments

1/3 of number k such that 8k + 5 and 8k + 7 are primes.

All numbers in A125821 are divisible by 3.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A125821(n)/3.

Example

0 is in the sequence since 24*0 + 5 = 5 and 24*0 + 7 = 7 are twin primes.

Mathematica

a = {}; Do[If[PrimeQ[8 n + 5] && PrimeQ[8 n + 3] && PrimeQ[n], AppendTo[a, n]], {n, 1, 10000}]; a
Select[Range[0, 500], AllTrue[24#+{5, 7}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Mar 08 2019 *)

Prog

(Magma) [n: n in [0..5000] |IsPrime(24*n+5)and IsPrime(24*n+7)] // Vincenzo Librandi, Nov 24 2010

Crossrefs

Cf. A125822, A139402, A139404.

Sequence in context: A293806 A310661 A351415 * A334927 A334920 A014455

Adjacent sequences: A139401 A139402 A139403 * A139405 A139406 A139407

Keyword

nonn

Author

Artur Jasinski, Apr 19 2008

Extensions

a(1) = 0 inserted by Vincenzo Librandi, Mar 25 2010

Status

approved