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A123704
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Numbers k such that (5^p - 3^p)/2 is prime, where p = prime(k).
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2
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6, 8, 9, 11, 15, 31, 48, 60, 314, 701, 940, 942, 2164, 2981, 3810, 6971, 12068, 13641, 16502
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OFFSET
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1,1
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COMMENTS
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Corresponding primes p = prime(a(n)) are listed in A121877.
Corresponding primes of the form (5^p - 3^p)/2 are listed in A123705.
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LINKS
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FORMULA
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MATHEMATICA
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Do[If[PrimeQ[(5^Prime[n] - 3^Prime[n])/2], Print[n]], {n, 1000}] (* Robert G. Wilson v, Jan 12 2007 *)
PrimePi[#]&/@Select[Prime[Range[1000]], PrimeQ[(5^#-3^#)/2]&] (* Harvey P. Dale, Sep 23 2018 *)
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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