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A023224 Numbers n such that n and 7n + 4 both prime. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..50.

MATHEMATICA

lst={}; Do[p=Prime[n]; If[PrimeQ[7*p+4], AppendTo[lst, p]], {n, 6!}]; lst [From Vladimir Joseph Stephan Orlovsky, Aug 16 2009]

PROG

(MAGMA) [n: n in [0..100000] | IsPrime(n) and IsPrime(7*n+4)] [From Vincenzo Librandi, Nov 19 2010]

CROSSREFS

Sequence in context: A130056 A136057 A177092 * A113743 A003215 A133323

Adjacent sequences:  A023221 A023222 A023223 * A023225 A023226 A023227

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified May 24 01:37 EDT 2013. Contains 225613 sequences.