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Search: id:A048862
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| A048862 |
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Number of primes in the reduced residue system of n-th primorial number(A002110). |
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+0
5
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| 0, 1, 7, 42, 338, 3242, 42324, 646021, 12283522, 300369786, 8028642999, 259488750732, 9414916809082
(list; graph; listen)
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OFFSET
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1,3
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FORMULA
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A000849(n) - A001221(A002110(n)) = A000720((A002110(n)) - n
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EXAMPLE
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n=3, 3rd primorial is 30, EulerPhi(30)=8, a(3)=8-1=7 since 1 is regarded here a nonprime. See A048597. n=4, 4th primorial is 210, size of its reduced residue system(RRS) is 48 of which 42 is prime and 6 is either composite or 1.
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CROSSREFS
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Cf. A002110, A000010, A000720, A048597, A007625, A048863.
Sequence in context: A152240 A073506 A025593 this_sequence A133669 A043064 A045800
Adjacent sequences: A048859 A048860 A048861 this_sequence A048863 A048864 A048865
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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)
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