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A128458 Numbers n such that 15^n - 2 is a prime. +0
10
1, 2, 3, 7, 12, 17, 19, 51, 65, 550, 1460, 1641, 7035 (list; graph; listen)
OFFSET

1,2

MATHEMATICA

Do[ f = 15^n - 2; If[ PrimeQ[ f ], Print[ {n, f} ] ], {n, 1, 1000} ]

Do[If[PrimeQ[15^n - 2], Print[n]], {n, 10^4}] -Ryan Propper (rpropper(AT)stanford.edu), Jun 06 2007

CROSSREFS

Cf. A084714 = smallest prime of the form (2n-1)^k - 2, or 0 if no such number exists. Cf. A128472 = smallest prime of the form (2n-1)^k - 2 for k>(2n-1), or 0 if no such number exists. Cf. A014224, A109080, A090669, A128455, A128457, A128459, A128460, A128461.

Sequence in context: A137767 A080140 A019568 this_sequence A066733 A049623 A061577

Adjacent sequences: A128455 A128456 A128457 this_sequence A128459 A128460 A128461

KEYWORD

hard,more,nonn

AUTHOR

Alexander Adamchuk (alex(AT)kolmogorov.com), Mar 14 2007

EXTENSIONS

550 from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), May 05 2007

3 more terms from Ryan Propper (rpropper(AT)stanford.edu), Jun 06 2007

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.


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