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A126992
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a(n) is the largest prime smaller than sqrt(prime(n)*prime(n+6)).
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2
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5, 7, 7, 13, 17, 19, 23, 23, 31, 37, 41, 47, 47, 53, 53, 61, 67, 73, 79, 83, 83, 89, 89, 97, 109, 113, 113, 113, 127, 127, 139, 139, 151, 151, 163, 163, 173, 173, 181, 181, 193, 199, 199, 199, 211, 211, 223, 233, 241, 241, 241, 251, 257, 263, 269
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OFFSET
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1,1
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LINKS
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MAPLE
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f:= n -> prevprime(ceil(sqrt(ithprime(n)*ithprime(n+6)))):
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MATHEMATICA
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Table[Prime[PrimePi[Sqrt[Prime[n]*Prime[n + 6]]]], {n, 1, 55}]
Table[NextPrime[Sqrt[Prime[n]Prime[n+6]], -1], {n, 60}] (* Harvey P. Dale, Jul 03 2019 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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