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A048980
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Difference between number of nonprimes and primes in reduced residue system of primorial numbers.
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0
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1, 1, 0, -6, -36, -196, -724, 7512, 366838, 11928316, 421130508, 14598816402, 584642184936, 25314953837836, 1128885572358548, 54492272309366314, 2950485568862138250, 213151926413154110951
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OFFSET
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0,4
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LINKS
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FORMULA
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EXAMPLE
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n=4, Q(4)=2*3*5*7=210, reduced residue system includes 48 terms:42 primes and 6 composites and 1: a(4)=6-42=-36.
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MATHEMATICA
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Table[Function[P, EulerPhi@ P - 2 # &[PrimePi@ P - n]]@ Product[Prime@ i, {i, n}], {n, 0, 12}] (* Michael De Vlieger, May 08 2017 *)
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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