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A121859
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Numbers n such that n!*3^n - 1 is prime.
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0
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1, 2, 12, 20, 38, 45, 46, 105, 117, 143, 214
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| 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
| Do[f=n!*3^n-1; If[PrimeQ[f], Print[{n, f}]], {n, 1, 214}]
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CROSSREFS
| Cf. A091415, A002982.
Sequence in context: A032407 A136725 A023534 * A145622 A174478 A145634
Adjacent sequences: A121856 A121857 A121858 * A121860 A121861 A121862
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KEYWORD
| nonn
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AUTHOR
| Alexander Adamchuk (alex(AT)kolmogorov.com), Sep 10 2006
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