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A138051
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Numbers n such that 27^n + 2 is prime.
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6
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0, 1, 5, 8, 12, 21, 41, 42, 81, 105, 121, 377, 501, 2401, 14597, 35381, 59476
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| All terms are the exact thirds of terms of A051783 that are divisible by 3.
Conjecture: 3^3^n+2 does not meet anti Fermat's conjecture. [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Aug 01 2010]
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LINKS
| Henri & Renaud Lifchitz, PRP Records.
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MATHEMATICA
| Do[ f = 27^n + 2; If[ PrimeQ[ f ], Print[ {n, f} ] ], {n, 1, 2500} ]
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CROSSREFS
| 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, A138049, A138050, A087886, A113481.
Cf. A176495.
Sequence in context: A134208 A115072 A114644 * A026279 A124434 A180930
Adjacent sequences: A138048 A138049 A138050 * A138052 A138053 A138054
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KEYWORD
| nonn
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AUTHOR
| Alexander Adamchuk (alex(AT)kolmogorov.com), Mar 02 2008
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EXTENSIONS
| a(15)-a(17) from A051783 by Ray Chandler (rayjchandler(AT)sbcglobal.net), Aug 06 2011
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