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Search: id:A102604
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| A102604 |
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Numbers n such that ((2*n)^n-1)/(2*n-1) is prime. |
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1
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OFFSET
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1,1
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COMMENT
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The next n in the sequence is > 4261 if exists
Note that (b^n-1)/(b-1) is prime only if n is prime, so all the elements in this sequence must be primes. - Marco Bodrato (marco2007(AT)bodrato.it), Oct 31 2007
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EXAMPLE
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(((2*2)^2)-1)/(2*2-1) = 15/3 = 5 prime so a(1)=2
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CROSSREFS
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Cf. A088790.
Sequence in context: A000317 A047024 A037843 this_sequence A119662 A163157 A000945
Adjacent sequences: A102601 A102602 A102603 this_sequence A102605 A102606 A102607
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KEYWORD
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more,nonn
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AUTHOR
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Pierre CAMI (pierrecami(AT)tele2.fr), Jan 29 2005
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