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Search: id:A128457
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| A128457 |
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Numbers n such that 13^n - 2 is a prime. |
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+0
13
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| 1, 2, 4, 5, 12, 78, 80, 90, 117, 120, 813, 1502
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OFFSET
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1,2
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COMMENT
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13320 is a term found by Lelio R Paula 11/2006.
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MATHEMATICA
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Do[ f = 13^n - 2; If[ PrimeQ[ f ], Print[ {n, f} ] ], {n, 1, 1000} ]
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CROSSREFS
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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, A128458, A128459, A128460, A128461.
Sequence in context: A091071 A050599 A102932 this_sequence A139485 A079407 A078652
Adjacent sequences: A128454 A128455 A128456 this_sequence A128458 A128459 A128460
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KEYWORD
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hard,more,nonn
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AUTHOR
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Alexander Adamchuk (alex(AT)kolmogorov.com), Mar 14 2007
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EXTENSIONS
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813 from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), May 05 2007
a(12) from M. F. Hasler (MHasler(AT)univ-ag.fr), Feb 07 2009
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