

A172209


Numbers n such that 18n  5 and 18n + 5 are primes.


0



1, 2, 6, 8, 9, 13, 16, 19, 21, 23, 28, 34, 36, 41, 42, 44, 49, 54, 57, 58, 61, 72, 78, 82, 83, 86, 89, 96, 99, 104, 111, 113, 132, 133, 149, 152, 154, 167, 173, 177, 187, 201, 211, 218, 236, 237, 247, 251, 258, 266, 273, 278, 288, 296, 302, 307, 314, 316, 317, 322
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..60.


EXAMPLE

a(1)=1 because 18*15=13 is prime and 18*1+5=23 is prime.


PROG

(MAGMA) [n: n in [1..2500]IsPrime(18*n5) and IsPrime(18*n+5)] // Vincenzo Librandi, Dec 19 2010
(PARI) forprime(p=2, 1e4, if(p%18==5 & isprime(p10), print1(p\18", "))) \\ Charles R Greathouse IV, May 25 2011


CROSSREFS

Cf. A000040, A172147, A172154.
Sequence in context: A034591 A047278 A242204 * A107737 A045138 A067704
Adjacent sequences: A172206 A172207 A172208 * A172210 A172211 A172212


KEYWORD

nonn,easy


AUTHOR

JuriStepan Gerasimov, Jan 29 2010


EXTENSIONS

Definition corrected and 49 inserted by R. J. Mathar and D. S. McNeil, May 22 2010
Corrected by D. S. McNeil, May 22 2010


STATUS

approved



