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A139404 Numbers k such that 24*k + 5 and 24*k + 7 are twin primes. 9
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 (list; graph; refs; listen; history; text; internal format)
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
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
Sequence in context: A293806 A310661 A351415 * A334927 A334920 A014455
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 19 2008
EXTENSIONS
a(1) = 0 inserted by Vincenzo Librandi, Mar 25 2010
STATUS
approved

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Last modified March 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)