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A172976
Primes p such that 2p - 1 and 6p - 1 are prime.
1
2, 3, 7, 19, 157, 199, 229, 379, 439, 577, 829, 877, 967, 997, 1009, 1279, 1429, 1459, 1657, 2137, 2539, 3067, 3169, 3187, 3319, 3739, 3769, 3967, 4159, 4357, 4447, 4909, 4987, 6079, 6379, 6427, 6709, 6967, 7219, 7297, 7639, 8209, 9049, 9067, 9157, 9277
OFFSET
1,1
PROG
(Magma) [p: p in PrimesUpTo(10000)|IsPrime(2*p-1) and IsPrime(6*p-1)] // Vincenzo Librandi, Jan 29 2011
(PARI) lista(nn) = forprime(p=2, nn, if(isprime(2*p - 1) && isprime(6*p - 1), print1(p, ", "))) \\ Iain Fox, Jan 20 2018
CROSSREFS
Sequence in context: A075487 A110498 A244917 * A171655 A293683 A006073
KEYWORD
nonn,easy,less
AUTHOR
EXTENSIONS
Corrected and extended by Charles R Greathouse IV, Mar 25 2010
STATUS
approved