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 A098035 a(n) = Sum_{k|n} mu(k+1), where mu() is the Moebius function. 3

%I

%S -1,-2,-1,-3,0,-3,-1,-3,0,-2,-1,-5,0,-1,0,-4,-1,-3,-1,-2,0,-3,-1,-5,1,

%T -1,0,-3,-2,-4,-1,-3,0,-1,0,-6,0,-1,0,-3,-2,-2,-1,-4,2,-3,-1,-6,-1,0,

%U -1,-3,-1,-2,0,-2,0,-4,-1,-6,0,-2,1,-2,0,-4,-1,-1,-2,-2,-1,-7,0,-1,1,-1,-2,-3,-1,-4,1,-4,-1,-4,1,-1,-2,-5,-1,-2,0,-3,0,-1

%N a(n) = Sum_{k|n} mu(k+1), where mu() is the Moebius function.

%H R. J. Mathar, <a href="/A098035/b098035.txt">Table of n, a(n) for n = 1..10000</a>

%e 12's divisors are 1, 2, 3, 4, 6 and 12. So a(12) = mu(2) + mu(3) + mu(4) + mu(5) + mu(7) + mu(13) = -1 - 1 + 0 - 1 - 1 - 1 = -5.

%t f[n_] := Plus @@ MoebiusMu[Divisors[n] + 1]; Table[ f[n], {n, 105}] (* _Robert G. Wilson v_, Nov 01 2004 *)

%Y Cf. A008683, A098018.

%K sign

%O 1,2

%A _Leroy Quet_, Oct 24 2004

%E More terms from _Robert G. Wilson v_, Nov 01 2004

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Last modified September 28 08:33 EDT 2020. Contains 337394 sequences. (Running on oeis4.)