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Search: id:A127908
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| A127908 |
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Primes of form (3^n + 2^n)/5. |
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2
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| 7, 463, 35839, 798167678837469920188160718521149336927, 24665899002341798194980052306171212216360861465143461865961807325057879, 50011490507388534231836533093323754201922663795625462006018551551727154205901960\ 78603421469034502777938287
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Numbers n such that (2^n + 3^n)/5 is prime are listed in A057469 = {3, 7, 11, 83, 149, 223, 599, 647, 1373, 8423, ...}.
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FORMULA
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a(n) = (2^A057469(n) + 3^A057469(n))/5.
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MATHEMATICA
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Do[f=(2^n+3^n)/5; If[PrimeQ[f], Print[{n, f}]], {n, 1, 1000}]
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CROSSREFS
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Cf. A057469.
Sequence in context: A009660 A024097 A160374 this_sequence A015105 A112949 A119621
Adjacent sequences: A127905 A127906 A127907 this_sequence A127909 A127910 A127911
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KEYWORD
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nonn
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AUTHOR
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Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 05 2007
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