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A153120 Primes p such that p^2 +- 42 are also primes. 6
5, 11, 13, 23, 53, 89, 101, 103, 109, 181, 197, 307, 313, 457, 467, 571, 691, 769, 863, 907, 1061, 1087, 1223, 1453, 1487, 1607, 1913, 2129, 2161, 2311, 2729, 2741, 2767, 2917, 3313, 3343, 3359, 3433, 4363, 4373, 4547, 4703, 4783, 4787, 4877, 5119, 5237 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

MATHEMATICA

fQ[n_]:=PrimeQ[n^2-42]&&PrimeQ[n^2+42]; lst={}; Do[If[fQ@Prime[n], AppendTo[lst, Prime[n]]], {n, 7!}]; lst

Select[Prime[Range[6000]], PrimeQ[#^2 - 42]&&PrimeQ[#^2 + 42]&] (* Vincenzo Librandi, Apr 08 2013 *)

PROG

(MAGMA) [p: p in PrimesUpTo(6000) | IsPrime(p^2-42) and IsPrime(p^2+42)]; // Vincenzo Librandi, Apr 08 2013

CROSSREFS

Cf. A153116, A153119.

Sequence in context: A192864 A309158 A161540 * A115782 A051654 A225754

Adjacent sequences:  A153117 A153118 A153119 * A153121 A153122 A153123

KEYWORD

nonn,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, Dec 18 2008

STATUS

approved

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Last modified January 19 09:35 EST 2020. Contains 331048 sequences. (Running on oeis4.)