A023215 Primes p such that 4*p + 7 is also prime.

3, 13, 19, 31, 43, 61, 103, 109, 139, 163, 241, 271, 313, 373, 379, 499, 523, 601, 613, 631, 643, 673, 709, 733, 739, 751, 769, 811, 823, 829, 883, 1021, 1033, 1051, 1063, 1069, 1129, 1171, 1231, 1249, 1291, 1381, 1459, 1483, 1531, 1549, 1579, 1621, 1663

Offset

1,1

Comments

Except for the first term, all terms are congruent to 1 (mod 6). - John Cerkan, Sep 07 2016

Links

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

Maple

A023215:=n->`if`(isprime(n) and isprime(4*n+7), n, NULL): seq(A023215(n), n=1..3*10^3); # Wesley Ivan Hurt, Sep 07 2016

Mathematica

Select[Prime[Range[300]], PrimeQ[4#+7]&] (* Harvey P. Dale, Jan 21 2011 *)

Prog

(Magma) [n: n in PrimesUpTo(500) | IsPrime(4*n+7)]; // Vincenzo Librandi, Nov 19 2010

Crossrefs

Subsequence of primes of A089986.

Sequence in context: A252090 A079419 A117300 * A185069 A023239 A229494

Adjacent sequences: A023212 A023213 A023214 * A023216 A023217 A023218

Keyword

nonn,easy

Author

David W. Wilson

Status

approved