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A070549
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a(n)=Card(k 0<k<=n such that mu(k)=-1).
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1
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0, 1, 2, 2, 3, 3, 4, 4, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 11, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 14, 15, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 19, 19, 20, 20, 20, 20, 20, 21, 22, 22, 22, 23, 24, 24, 25, 25, 25, 25, 25, 26
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| mu(k)=-1 if k is the product of an odd number of distinct primes. See A057627 for mu(k)=0.
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PROG
| (PARI) for(n=1, 150, print1(sum(i=1, n, if(moebius(i)+1, 0, 1)), ", "))
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CROSSREFS
| Sequence in context: A082447 A139789 A000720 * A074796 A061070 A117695
Adjacent sequences: A070546 A070547 A070548 * A070550 A070551 A070552
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KEYWORD
| easy,nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), May 02 2002
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