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A023225 Numbers n such that n and 7n + 6 are both prime. 16
5, 11, 13, 19, 23, 31, 41, 43, 59, 61, 71, 83, 103, 109, 113, 149, 151, 173, 179, 199, 211, 223, 229, 233, 241, 263, 269, 281, 283, 353, 373, 379, 383, 389, 419, 421, 431, 433, 439, 479, 499, 503, 541, 563, 569, 571, 593, 613, 619, 631, 641, 643, 683, 709, 719, 739, 761 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

MATHEMATICA

Select[Prime[Range[2000]], PrimeQ[7 # + 6]&] (* Vincenzo Librandi, Feb 02 2014 *)

PROG

(MAGMA) [n: n in [0..1000] | IsPrime(n) and IsPrime(7*n+6)]; // Vincenzo Librandi, Nov 20 2010

(PARI) is(n)=isprime(7*n+6)&&isprime(n) \\ Charles R Greathouse IV, Jul 02 2013

CROSSREFS

Sequence in context: A079019 A191034 A222219 * A206581 A292940 A098085

Adjacent sequences:  A023222 A023223 A023224 * A023226 A023227 A023228

KEYWORD

nonn,easy

AUTHOR

David W. Wilson

STATUS

approved

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Last modified January 23 22:36 EST 2020. Contains 331177 sequences. (Running on oeis4.)