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Search: id:A138049
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| A138049 |
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Numbers n such that 21^n + 2 is prime. |
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+0
6
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OFFSET
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1,3
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LINKS
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Henri & Renaud Lifchitz, PRP Records.
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MATHEMATICA
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Do[ f = 21^n + 2; If[ PrimeQ[ f ], Print[ {n, f} ] ], {n, 1, 310} ]
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CROSSREFS
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Cf. A051783 = Numbers n such that 3^n + 2 is prime. Cf. A087885 = Numbers n such that 5^n + 2 is prime. Cf. A090649, A109076, A113480, A138048, A138050, A138051, A087886, A138052, A138053, A138054, A138055, A138056, A138057, A138058, A138059, A138060, A113481.
Sequence in context: A026080 A071795 A059501 this_sequence A099387 A036440 A103001
Adjacent sequences: A138046 A138047 A138048 this_sequence A138050 A138051 A138052
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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 02 2008
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EXTENSIONS
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One more term from Herman Jamke (hermanjamke(AT)fastmail.fm), May 01 2008
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