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Search: id:A121859
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| A121859 |
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Numbers n such that n!*3^n - 1 is prime. |
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+0
1
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| 1, 2, 12, 20, 38, 45, 46, 105, 117, 143, 214
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Corresponding primes of the form n!*3^n - 1 are a(n)!*3^a(n) - 1 ={2,17,254561089305599,8483004771271882804592639999,...}.
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MATHEMATICA
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Do[f=n!*3^n-1; If[PrimeQ[f], Print[{n, f}]], {n, 1, 214}]
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CROSSREFS
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Cf. A091415, A002982.
Sequence in context: A032407 A136725 A023534 this_sequence A145622 A145634 A145610
Adjacent sequences: A121856 A121857 A121858 this_sequence A121860 A121861 A121862
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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), Sep 10 2006
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