A124065 Numbers k such that 8*k - 1 and 8*k + 1 are twin primes.

9, 24, 30, 39, 54, 75, 129, 144, 165, 186, 201, 234, 261, 264, 324, 336, 339, 375, 390, 396, 420, 441, 459, 471, 516, 534, 600, 621, 654, 660, 690, 705, 735, 795, 819, 849, 870, 891, 936, 945, 1011, 1029, 1125, 1155, 1179, 1215, 1221, 1251, 1284, 1395, 1419

Offset

1,1

Links

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

Example

9 is in the sequence since 8*9 - 1 = 71 and 8*9 + 1 = 73 are twin primes.

Mathematica

Select[Range[1500], And @@ PrimeQ[{-1, 1} + 8# ] &] (* Ray Chandler, Nov 16 2006 *)

Prog

(Magma) [n: n in [1..2000] | IsPrime(8*n+1) and IsPrime(8*n-1)] // Vincenzo Librandi, Mar 08 2010
(Python)
from sympy import isprime
def ok(n): return isprime(8*n - 1) and isprime(8*n + 1)
print(list(filter(ok, range(1420)))) # Michael S. Branicky, Sep 24 2021

Crossrefs

Intersection of A005122 and A005123.

Cf. A040040, A045753, A002822, A124518, A124519, A124520, A124521, A124522, A063983.

Sequence in context: A223297 A317493 A102217 * A121453 A003343 A345843

Adjacent sequences: A124062 A124063 A124064 * A124066 A124067 A124068

Keyword

nonn

Author

Artur Jasinski, Nov 04 2006

Extensions

Extended by Ray Chandler, Nov 16 2006

Status

approved