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A172122
Primes p such that 7*p^2+7*p+1 is also prime.
1
2, 5, 17, 29, 59, 197, 227, 257, 317, 359, 467, 509, 569, 587, 797, 929, 1097, 1187, 1259, 1307, 1439, 1637, 1697, 1847, 1877, 1997, 2027, 2069, 2099, 2237, 2297, 2399, 2459, 2477, 2657, 2687, 2729, 2939, 3167, 3359, 3407, 3467, 3659, 3677, 4019, 4079
OFFSET
1,1
LINKS
MATHEMATICA
Select[Prime[Range[3000]], PrimeQ[7 #^2 + 7 # + 1]&] (* Vincenzo Librandi, Apr 16 2013 *)
PROG
(Magma) [p: p in PrimesUpTo(4100) | IsPrime(7*p^2 + 7*p + 1)]; // Vincenzo Librandi, Apr 16 2013
CROSSREFS
Cf. A171139.
Sequence in context: A244085 A019353 A106882 * A101009 A269018 A066649
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Jan 26 2010
STATUS
approved