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URL: https://oeis.org/A121859

⇱ A121859 - OEIS

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A121859
Numbers n such that n!*3^n - 1 is prime.
2
1, 2, 12, 20, 38, 45, 46, 105, 117, 143, 214, 1835, 2931, 7703, 11542, 19225
OFFSET
1,2
COMMENTS
Corresponding primes of the form n!*3^n - 1 are a(n)!*3^a(n) - 1 ={2,17,254561089305599,8483004771271882804592639999,...}.
a(17) > 25000. - Robert Price, Jul 22 2013
MATHEMATICA
Do[f=n!*3^n-1; If[PrimeQ[f], Print[{n, f}]], {n, 1, 25000}]
CROSSREFS
Sequence in context: A326238 A226399 A353399 * A145622 A266050 A291698
KEYWORD
nonn
AUTHOR
Alexander Adamchuk, Sep 10 2006
EXTENSIONS
a(12)-a(16) from Robert Price, Jul 22 2013
STATUS
approved