A174915 Numbers p such that p, q=p+2 and p+2*q are all primes.

3, 5, 11, 41, 59, 101, 179, 191, 269, 311, 431, 521, 599, 821, 881, 1019, 1061, 1151, 1229, 1301, 1451, 1481, 1619, 1721, 1949, 2081, 2111, 2141, 2729, 2999, 3299, 3821, 4001, 4091, 4259, 4421, 4799, 4931, 5009, 5519, 5639, 5849, 6131, 6359, 6689, 6701

Offset

1,1

Comments

Subsequence of A175914.

Links

Zak Seidov, Table of n, a(n) for n = 1..1000

Mathematica

lst={}; Do[p1=Prime[n]; p2=p1+2; If[PrimeQ[p2]&&PrimeQ[p1+2*p2], AppendTo[lst, p1]], {n, 7!}]; lst
Reap[Do[p = Prime[m]; If[PrimeQ[p + 2 ] && PrimeQ[3 p + 4], Sow[p]], {m, 10^3}]][[2, 1]](* Zak Seidov, Oct 14 2012 *)
Transpose[Select[Partition[Prime[Range[1000]], 2, 1], #[[2]]-#[[1]]==2 && PrimeQ[ #[[1]]+2#[[2]]]&]][[1]] (* Harvey P. Dale, Jan 28 2015 *)

Prog

(PARI) forprime(p=2, 7000, q=p+2; if(isprime(q)&& isprime(p+2*q), print1(p, ", ")))
(Magma) [p: p in PrimesUpTo(7000) | IsPrime(p+2) and IsPrime(3*p+4)]; // Vincenzo Librandi, Jan 29 2015

Crossrefs

Cf. A001359, A174913, A175914.

Sequence in context: A060881 A035345 A254401 * A162250 A055511 A236457

Adjacent sequences: A174912 A174913 A174914 * A174916 A174917 A174918

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Apr 02 2010

Extensions

Definition and comment corrected by Zak Seidov, Dec 06 2010

Status

approved