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A008966 1 if n is square-free, else 0. +0
16
1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0 (list; graph; listen)
OFFSET

1,1

COMMENT

a(n) depends only on prime signature of n (cf. A025487). So a(24) = a(375) since 24=2^3*3 and 375=3*5^3 both have prime signature (3,1).

LINKS

Eric Weisstein's World of Mathematics, Moebius Function

FORMULA

Dirichlet g.f. zeta(s)/zeta(2s).

a(n) = abs(mu(n)), where mu is the Moebius function (A008683).

a(n) = 0^(bigomega(n)-omega(n)), where bigomega(n) and omega(n) are the numbers of prime factors of n with and without repetition (A001222, A001221, A046660). - Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Apr 05 2003

Multiplicative with p^e -> 0^(e-1), p prime and e>0. - Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Jul 15 2003

a(n) = 0^(A046951(n)-1). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 20 2007

PROGRAM

(MuPAD) func(abs(numlib::moebius(n)), n):

(MAGMA) [ Abs(MoebiusMu(n)) : n in [1..100]];

(PARI) a(n)=if(n<1, 0, direuler(p=2, n, 1+X))[n]

CROSSREFS

Cf. A008683, A008836.

Sequence in context: A075437 A130047 A008683 this_sequence A080323 A069158 A133639

Adjacent sequences: A008963 A008964 A008965 this_sequence A008967 A008968 A008969

KEYWORD

easy,nonn,mult

AUTHOR

njas

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Last modified July 26 23:19 EDT 2008. Contains 142293 sequences.


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