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A109887
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Numbers n such that 3^n + phi(n) is prime.
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0
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3, 4, 10, 20, 44, 60, 583, 677, 947, 1182, 12048, 16018, 74316
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| All terms correspond to certified primes (Primo 2.2.0 beta). No more terms through 10000.
a(14) > 10^5. [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 06 2010]
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MATHEMATICA
| Do[If[PrimeQ[3^n + EulerPhi[n]], Print[n]], {n, 1, 10000}]
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CROSSREFS
| Sequence in context: A171160 A139797 A036649 * A200981 A103038 A143108
Adjacent sequences: A109884 A109885 A109886 * A109888 A109889 A109890
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KEYWORD
| hard,nonn
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AUTHOR
| Ryan Propper (rpropper(AT)stanford.edu), Aug 31 2005
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EXTENSIONS
| a(11)-a(13) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 06 2010
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