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A109080 Numbers n such that 5^n - 2 is prime. +0
14
1, 2, 14, 26, 50, 126, 144, 260, 624, 1424, 10472, 19784, 24558 (list; graph; listen)
OFFSET

1,2

COMMENT

No more terms through 18000.

No more terms through 50000. [From Ryan Propper (rpropper(AT)cs.stanford.edu), Dec 10 2008]

EXAMPLE

5^14 - 2 = 6103515623 is prime, hence 14 is in the sequence.

MATHEMATICA

Do[If[PrimeQ[5^n - 2], Print[n]], {n, 1, 18000}]

CROSSREFS

Sequence in context: A109255 A051222 A017545 this_sequence A032461 A072390 A117705

Adjacent sequences: A109077 A109078 A109079 this_sequence A109081 A109082 A109083

KEYWORD

hard,nonn

AUTHOR

Ryan Propper (rpropper(AT)stanford.edu), Jun 18 2005

EXTENSIONS

Two more terms. Ryan Propper (rpropper(AT)cs.stanford.edu), Dec 10 2008

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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