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A098035 a(n) = Sum_{k|n} mu(k+1), where mu() is the Moebius function. 3
-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, -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, -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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..10000

EXAMPLE

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.

MATHEMATICA

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

CROSSREFS

Cf. A008683, A098018.

Sequence in context: A194665 A004563 A146094 * A079055 A122170 A066029

Adjacent sequences:  A098032 A098033 A098034 * A098036 A098037 A098038

KEYWORD

sign

AUTHOR

Leroy Quet, Oct 24 2004

EXTENSIONS

More terms from Robert G. Wilson v, Nov 01 2004

STATUS

approved

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Last modified March 22 17:25 EDT 2019. Contains 321422 sequences. (Running on oeis4.)