A023225 Primes p such that 7*p + 6 is also prime.

5, 11, 13, 19, 23, 31, 41, 43, 59, 61, 71, 83, 103, 109, 113, 149, 151, 173, 179, 199, 211, 223, 229, 233, 241, 263, 269, 281, 283, 353, 373, 379, 383, 389, 419, 421, 431, 433, 439, 479, 499, 503, 541, 563, 569, 571, 593, 613, 619, 631, 641, 643, 683, 709, 719, 739, 761

Offset: 1

Author

David W. Wilson

Keywords

• nonn
• easy

Links

• John Cerkan, Table of n, a(n) for n = 1..10000

Programs

Magma

[n: n in [0..1000] | IsPrime(n) and IsPrime(7*n+6)]; // Vincenzo Librandi, Nov 20 2010

Mathematica

Select[Prime[Range[2000]], PrimeQ[7 # + 6]&] (* Vincenzo Librandi, Feb 02 2014 *)

PARI

is(n)=isprime(7*n+6)&&isprime(n) \\ Charles R Greathouse IV, Jul 02 2013