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Search: id:A067393
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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
1
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| 1, 1, 1, 1, 1, 5, 67, 481, 4989, 51979, 570755, 5865449, 74226518, 904772855, 13111019601, 202135743076, 3307158697867, 53256981940267
(list; graph; listen)
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OFFSET
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0,6
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FORMULA
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a(n)=phi(n!)-pi(n!)+pi(n)= A000010(n!)-A000720(n!)+A000720(n).
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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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Cf. A000142, A000720, A003604, A000010, A048855.
Sequence in context: A059852 A057171 A142009 this_sequence A113265 A124435 A123034
Adjacent sequences: A067390 A067391 A067392 this_sequence A067394 A067395 A067396
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KEYWORD
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more,nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Jan 22 2002
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