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A062563
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Sum_{k=1...n} d(k)* mu(k), where d(k) is the number of divisors function.
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1
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1, -1, -3, -3, -5, -1, -3, -3, -3, 1, -1, -1, -3, 1, 5, 5, 3, 3, 1, 1, 5, 9, 7, 7, 7, 11, 11, 11, 9, 1, -1, -1, 3, 7, 11, 11, 9, 13, 17, 17, 15, 7, 5, 5, 5, 9, 7, 7, 7, 7, 11, 11, 9, 9, 13, 13, 17, 21, 19, 19, 17, 21, 21, 21, 25, 17, 15, 15, 19, 11, 9, 9, 7, 11, 11, 11, 15, 7, 5, 5, 5, 9, 7, 7, 11, 15, 19, 19, 17, 17, 21, 21, 25, 29, 33, 33, 31
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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FORMULA
| Also a(n)=sum(k=1,n,2^omega(k)*mu(k)) - Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 13 2007
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PROG
| (PARI) v=[]; for(n=1, 250, v=concat(v, sum(k=1, n, numdiv(k)*moebius(k)))); v
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CROSSREFS
| Sequence in context: A103786 A067462 A021753 * A091931 A109824 A011399
Adjacent sequences: A062560 A062561 A062562 * A062564 A062565 A062566
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KEYWORD
| sign
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AUTHOR
| Jason Earls (zevi_35711(AT)yahoo.com), Jul 03 2001
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