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A067393
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Number of nonprimes among the numbers in {1,2,3,...,n!} which are relatively prime to n!.
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0
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1, 1, 1, 1, 1, 5, 67, 481, 4989, 51979, 570755, 5865449, 74226518, 904772855, 13111019601, 202135743076, 3307158697867, 53256981940267, 974755766640247, 17629139875485487, 357191085875727470, 7585952737111971220, 168542590546266903340, 3718034609300727209976
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OFFSET
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0,6
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LINKS
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FORMULA
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EXAMPLE
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For n=5, n!=120, a(5)=phi(120)-pi(120)+pi(5)=32-30+3=5; the 5 nonprimes are 1,49,77,91,119.
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MATHEMATICA
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a[n_] := EulerPhi[ n! ]-PrimePi[ n! ]+PrimePi[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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EXTENSIONS
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STATUS
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approved
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