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A087802
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Sum(mu(d): d nonprime divisor of n), mu=A008683.
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2
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1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 3, 1, 1, 2, 2, 2, 2, 1, 2, 2, 2, 1, 3, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 3, 1, 2, 2, 1, 2, 3, 1, 2, 2, 3, 1, 2, 1, 2, 2, 2, 2, 3, 1, 2, 1, 2, 1, 3, 2, 2, 2, 2, 1, 3, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 1, 3
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,6
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COMMENTS
| A064372 and this sequence first differ at term 64: A064372(64)=2 and a(64)=1. - Rick L. Shepherd (rshepherd2(AT)hotmail.com), Mar 07 2004
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FORMULA
| a(n) = if n=1 then 1 else A001221(n). - Vladeta Jovovic (vladeta(AT)eunet.rs), Oct 17 2003
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EXAMPLE
| Divisors of n=42: {1,2,3,6,7,14,21,42}, a(42) = mu(1)+mu(6)+mu(14)+mu(21)+mu(42) = 1+1+1+1-1 = 3.
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PROG
| (PARI) A087802(n) = sumdiv(n, d, if(!isprime(d), moebius(d)))
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CROSSREFS
| Cf. A023890, A033273. Different from A079553.
Sequence in context: A125029 A062893 A158210 * A079553 A001221 A064372
Adjacent sequences: A087799 A087800 A087801 * A087803 A087804 A087805
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KEYWORD
| nonn
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 11 2003
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