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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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,6
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FORMULA
| a(n)=phi(n!)-pi(n!)+pi(n)= A000010(n!)-A000720(n!)+A000720(n).
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EXAMPLE
| 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
| a[n_] := EulerPhi[ n! ]-PrimePi[ n! ]+PrimePi[n]
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CROSSREFS
| Cf. A000142, A000720, A003604, A000010, A048855.
Sequence in context: A059852 A057171 A142009 * A113265 A124435 A123034
Adjacent sequences: A067390 A067391 A067392 * A067394 A067395 A067396
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KEYWORD
| more,nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Jan 22 2002
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EXTENSIONS
| a(18)-a(19) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Mar 24 2011
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