A023224 Primes p such that 7*p + 4 is also prime.

7, 19, 37, 61, 79, 97, 139, 151, 157, 211, 229, 271, 307, 349, 379, 457, 487, 547, 571, 601, 607, 619, 631, 709, 751, 757, 769, 829, 877, 907, 937, 997, 1021, 1069, 1117, 1129, 1237, 1249, 1291, 1327, 1429, 1447, 1471, 1489, 1549, 1567, 1579, 1621, 1627, 1699

Offset

1,1

Comments

Subsequence of A024902. All terms are congruent to 1 mod 6 because 7(6n + 5) + 4 is divisible by 3. - John Cerkan, Jul 08 2016

Links

John Cerkan, Table of n, a(n) for n = 1..10000

Maple

A023224:=n->`if`(isprime(n) and isprime(7*n+4), n, NULL): seq(A023224(n), n=1..5000); # Wesley Ivan Hurt, Jul 08 2016

Mathematica

Select[Prime[Range[300]], PrimeQ[7# + 4] &] (* Alonso del Arte, Nov 21 2018 *)

Prog

(Magma) [n: n in [0..100000] | IsPrime(n) and IsPrime(7*n+4)] // Vincenzo Librandi, Nov 19 2010
(PARI) lista(nn) = for(p=2, nn, if(isprime(7*p+4), print1(p, ", "))); \\ Altug Alkan, Jul 08 2016

Crossrefs

Cf. A024902.

Sequence in context: A130056 A136057 A177092 * A113743 A003215 A308685

Adjacent sequences: A023221 A023222 A023223 * A023225 A023226 A023227

Keyword

nonn

Author

David W. Wilson

Status

approved