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A087885
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Numbers n such that 5^n + 2 is a prime.
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9
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0, 1, 3, 17, 143, 261, 551, 2285, 18731, 18995, 19751, 62067, 98051
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| Terms <= 551 correspond to certified primes.
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LINKS
| Henri & Renaud Lifchitz, PRP Records.
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EXAMPLE
| a(3)=3 is a member because 5^3 + 2 = 127 is a prime.
5^17 + 2 = 762939453127 is prime, hence 17 is a term.
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MATHEMATICA
| Do[If[PrimeQ[5^n + 2], Print[n]], {n, 1, 10000}] (Propper)
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CROSSREFS
| Cf. A051783, 3^n + 2 is a prime.
Sequence in context: A120022 A001865 A189001 * A178685 A198860 A051442
Adjacent sequences: A087882 A087883 A087884 * A087886 A087887 A087888
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KEYWORD
| hard,nonn
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AUTHOR
| Donald S. McDonald (don.mcdonald(AT)paradise.net.nz), Oct 13 2003
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EXTENSIONS
| {551, 2285} from Ryan Propper (rpropper(AT)stanford.edu), Jun 17 2005
{18731, 18995, 19751, 62067} found by Mike Oakes in 2003. - Alexander Adamchuk (alex(AT)kolmogorov.com), Mar 02 2008
Edited by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jul 27 2011
98051 from Ray Chandler (rayjchandler(AT)sbcglobal.net), Jul 28 2011
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