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A157200
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Numbers n such that n*(2n)^n-1 is a prime.
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0
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2, 3, 6, 7, 12, 21, 113, 404, 735, 1944, 4973
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Conjecture: there are infinite numbers of such kind of primes.
a(12) > 10000. [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Aug 31 2010]
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EXAMPLE
| n=2, 2*(2*2)^2-1 = 31 is a prime number; n=3, 3^(2*3)^2-1 = 107 is a prime number; and so on
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MATHEMATICA
| Do[cp=n*(2*n)^n-1; If[PrimeQ[cp], Print[n]], {n, 1, 2000}] This generate the listed first 10 elements.
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CROSSREFS
| Sequence in context: A064689 A144120 A073712 * A167415 A018511 A182708
Adjacent sequences: A157197 A157198 A157199 * A157201 A157202 A157203
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KEYWORD
| hard,nice,nonn
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AUTHOR
| Lei Zhou (lzhou5(AT)emory.edu), Feb 25 2009
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EXTENSIONS
| a(11) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Aug 31 2010
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