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A087802 Sum(mu(d): d nonprime divisor of n), mu=A008683. +0
2
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; listen)
OFFSET

1,6

COMMENT

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

FORMULA

a(n) = if n=1 then 1 else A001221(n). - Vladeta Jovovic (vladeta(AT)Eunet.yu), Oct 17 2003

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.

PROGRAM

(PARI) A087802(n) = sumdiv(n, d, if(!isprime(d), moebius(d)))

CROSSREFS

Cf. A023890, A033273. Different from A079553.

Sequence in context: A103765 A125029 A062893 this_sequence A079553 A001221 A064372

Adjacent sequences: A087799 A087800 A087801 this_sequence A087803 A087804 A087805

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Oct 11 2003

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.


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