A173641 Primes p such that p^2+4 and p^2-6 are both prime.

3, 5, 7, 13, 17, 47, 67, 73, 97, 167, 193, 293, 317, 373, 463, 487, 503, 593, 607, 677, 787, 823, 827, 1087, 1613, 1637, 1987, 2477, 2543, 2687, 2777, 2833, 2903, 2957, 3023, 3583, 3593, 3917, 4093

Offset: 1

Author

Giovanni Teofilatto, Nov 24 2010

Keywords

• nonn
• easy

Comments

p^2+4 and p^2-6 are both primes if a(n)^2+4 is in the sequence A172240 such that A172240(n) - 10 is also prime.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Programs

Magma

[p: p in PrimesUpTo(4100) | IsPrime(p^2+4)and IsPrime(p^2-6)]; // Vincenzo Librandi, Apr 16 2013

Mathematica

Select[Prime[Range[800]], PrimeQ[#^2 + 4]&& PrimeQ[#^2 - 6]&] (* Vincenzo Librandi, Apr 16 2013 *)

Sage

A173641 = list(p for p in primes(10^5) if is_prime(p^2+4) and is_prime(p^2-6))

Extensions

Corrected and extended by D. S. McNeil, Nov 24 2010