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

1,1

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

Mathematica

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

Prog

(Sage) A173641 = list(p for p in primes(10^5) if is_prime(p^2+4) and is_prime(p^2-6))
(Magma) [p: p in PrimesUpTo(4100) | IsPrime(p^2+4)and IsPrime(p^2-6)]; // Vincenzo Librandi, Apr 16 2013

Crossrefs

Sequence in context: A378189 A226794 A300748 * A153645 A106878 A192294

Adjacent sequences: A173638 A173639 A173640 * A173642 A173643 A173644

Keyword

nonn,easy

Author

Giovanni Teofilatto, Nov 24 2010

Extensions

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

Status

approved