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A174281 Primes p such that 20*p^2+32*p+13 is also prime. 1
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 (list; graph; refs; listen; history; text; internal format)
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: A306636 A101150 A276322 * A301916 A038875 A019334

Adjacent sequences:  A174278 A174279 A174280 * A174282 A174283 A174284

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Mar 15 2010

STATUS

approved

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Last modified October 14 07:19 EDT 2019. Contains 327995 sequences. (Running on oeis4.)