A174281 Primes p such that 20*p^2+32*p+13 is also prime.

2, 5, 7, 17, 19, 23, 29, 47, 73, 83, 89, 97, 107, 113, 127, 137, 149, 163, 197, 227, 229, 233, 239, 257, 269, 307, 359, 367, 373, 379, 439, 449, 557, 569, 619, 647, 673, 727, 739, 769, 797, 827, 877, 883, 919, 977, 983, 997, 1009, 1033, 1039, 1087, 1117, 1123

Offset

1,1

Links

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

Example

For p=2, 20*2^2+32*2+13=157; p=5, 20*5^2+32*5+13=673.

Mathematica

Select[Prime[Range[200]], PrimeQ[20 #^2 + 32 # + 13]&] (* Vincenzo Librandi, Apr 16 2013 *)

Prog

(Magma) [p: p in PrimesUpTo(2000)| IsPrime(20*p^2+32*p+13)];

Crossrefs

Cf. A154414.

Sequence in context: A101150 A276322 A337986 * A301916 A038875 A019334

Adjacent sequences: A174278 A174279 A174280 * A174282 A174283 A174284

Keyword

nonn,easy

Author

Vincenzo Librandi, Mar 15 2010

Status

approved