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A059803
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Numbers n such that 9^n - 8^n is prime.
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1
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2, 7, 29, 31, 67, 149, 401, 2531, 19913, 30773, 53857, 170099
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Some of the larger entries may only correspond to probable primes.
In general, for any positive integers n, a and b, a>b, a necessary condition for a^n-b^n to be prime is that either a-b=1 and n be a prime or n=1 and a-b be prime. (Librandi - Magidin - Hagman) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Sep 12 2010]
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CROSSREFS
| Cf. A000043, A057468, A059801-...
Sequence in context: A013181 A191478 A122118 * A076043 A180448 A116968
Adjacent sequences: A059800 A059801 A059802 * A059804 A059805 A059806
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KEYWORD
| nonn,hard
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AUTHOR
| Mike Oakes (Mikeoakes2(AT)aol.com), Feb 23 2001
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EXTENSIONS
| Three more terms found by Jean-Louis Charton in 2004-2005: a(9) = 30773, a(10) = 53857, a(11) = 170099. - Alexander Adamchuk (alex(AT)kolmogorov.com), Dec 08 2006
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