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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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 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 Adjacent sequences: A172119 A172120 A172121 * A172123 A172124 A172125 KEYWORD nonn,easy AUTHOR _Vincenzo Librandi_, Jan 26 2010 STATUS approved

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Last modified February 24 01:16 EST 2024. Contains 370288 sequences. (Running on oeis4.)