A172122 Primes p such that 7*p^2+7*p+1 is also prime.

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

Author

Vincenzo Librandi, Jan 26 2010

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A171139.

Programs

Magma

[p: p in PrimesUpTo(4100) | IsPrime(7*p^2 + 7*p + 1)]; // Vincenzo Librandi, Apr 16 2013

Mathematica

Select[Prime[Range[3000]], PrimeQ[7 #^2 + 7 # + 1]&] (* Vincenzo Librandi, Apr 16 2013 *)