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Search: id:A109080
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| A109080 |
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Numbers n such that 5^n - 2 is prime. |
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+0
14
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| 1, 2, 14, 26, 50, 126, 144, 260, 624, 1424, 10472, 19784, 24558
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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No more terms through 18000.
No more terms through 50000. [From Ryan Propper (rpropper(AT)cs.stanford.edu), Dec 10 2008]
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EXAMPLE
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5^14 - 2 = 6103515623 is prime, hence 14 is in the sequence.
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MATHEMATICA
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Do[If[PrimeQ[5^n - 2], Print[n]], {n, 1, 18000}]
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CROSSREFS
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Sequence in context: A109255 A051222 A017545 this_sequence A032461 A072390 A117705
Adjacent sequences: A109077 A109078 A109079 this_sequence A109081 A109082 A109083
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KEYWORD
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hard,nonn
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AUTHOR
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Ryan Propper (rpropper(AT)stanford.edu), Jun 18 2005
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EXTENSIONS
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Two more terms. Ryan Propper (rpropper(AT)cs.stanford.edu), Dec 10 2008
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