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A125744
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Primes p such that (3^p + 3^((p + 1)/2) + 1)/7 is prime.
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2
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11, 37, 47, 97, 167, 877, 2027, 2293, 3011, 6803, 8423, 50221, 152809, 505823
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OFFSET
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1,1
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COMMENTS
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PrimePi[ a(n) ] = {5, 12, 15, 25, 39, 151, 307, 341, ...}.
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LINKS
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MATHEMATICA
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Do[p=Prime[n]; f=(3^p+3^((p+1)/2)+1)/7; If[PrimeQ[f], Print[{n, p}]], {n, 1, 341}]
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CROSSREFS
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KEYWORD
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hard,more,nonn
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AUTHOR
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EXTENSIONS
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a(9)-a(12) from Lelio R Paula (lelio(AT)sknet.com.br), May 09 2008
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STATUS
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approved
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