A051507 Primes p such that p*q+2 is prime, where q is next prime after p.

3, 5, 7, 13, 19, 67, 149, 179, 229, 239, 241, 269, 277, 307, 313, 397, 401, 419, 439, 487, 569, 613, 643, 701, 823, 863, 887, 1051, 1289, 1319, 1489, 1609, 1693, 1783, 1873, 1999, 2143, 2239, 2309, 2423, 2539, 2549, 2593, 2617, 2729, 2753, 2819

Offset

1,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Mathematica

Prime[Select[Range[1000], PrimeQ[Prime[#]*Prime[# + 1] + 2] &]]
Reap[Do[If[PrimeQ[(p=Prime[k])*Prime[k+1]+2], Sow[p]], {k, 1, 430}]][[2, 1]] (* Zak Seidov, Dec 05 2010 *)

Prog

(Sage) A051507 = list(p for p in primes(10**4) if is_prime(p*next_prime(p)+2)) # D. S. McNeil, Dec 04 2010
(PARI) p=2; forprime(q=3, 1e4, if(isprime(p*q+2), print1(p", ")); p=q) \\ Charles R Greathouse IV, May 01 2011

Crossrefs

Cf. A048880.

Sequence in context: A154700 A187872 A180450 * A173145 A347834 A060274

Adjacent sequences: A051504 A051505 A051506 * A051508 A051509 A051510

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved