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A255510
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Numbers n of the form 3^k such that sigma(n) is a prime p.
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1
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OFFSET
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1,1
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COMMENTS
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Powers of 3 from A023194 (numbers n such that sigma(n) is a prime).
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LINKS
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FORMULA
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MATHEMATICA
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Select[3^Range[0, 110], PrimeQ[DivisorSigma[1, #]]&] (* Harvey P. Dale, Mar 29 2015 *)
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PROG
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(Magma) [(3^n): n in [1..1000] | IsPrime((SumOfDivisors(3^n)))]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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