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A023215
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Numbers n such that n and 4n + 7 both prime.
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0
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3, 13, 19, 31, 43, 61, 103, 109, 139, 163, 241, 271, 313, 373, 379, 499, 523, 601, 613, 631, 643, 673, 709, 733, 739, 751, 769, 811, 823, 829, 883, 1021, 1033, 1051, 1063, 1069, 1129, 1171, 1231, 1249, 1291, 1381, 1459, 1483, 1531, 1549, 1579, 1621, 1663
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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MATHEMATICA
| f[n_]:=PrimeQ[4*n+7]; lst={}; Do[p=Prime[n]; If[f[p], AppendTo[lst, p]], {n, 6!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Oct 03 2009]
Select[Prime[Range[300]], PrimeQ[4#+7]&] [From Harvey P. Dale, Jan. 21, 2011]
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PROG
| (MAGMA) [n: n in [0..1000] | IsPrime(n) and IsPrime(4*n+7)] [From V. Librandi, Nov 19 2010]
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CROSSREFS
| Sequence in context: A168425 A079419 A117300 * A185069 A023239 A018621
Adjacent sequences: A023212 A023213 A023214 * A023216 A023217 A023218
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KEYWORD
| nonn
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AUTHOR
| David W. Wilson (davidwwilson(AT)comcast.net)
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