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 A327278 a(n) = Sum_{d|n, d odd} d * mu(d) * mu(n/d). 3
 1, -1, -4, 0, -6, 4, -8, 0, 3, 6, -12, 0, -14, 8, 24, 0, -18, -3, -20, 0, 32, 12, -24, 0, 5, 14, 0, 0, -30, -24, -32, 0, 48, 18, 48, 0, -38, 20, 56, 0, -42, -32, -44, 0, -18, 24, -48, 0, 7, -5, 72, 0, -54, 0, 72, 0, 80, 30, -60, 0, -62, 32, -24, 0, 84, -48, -68, 0, 96 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Dirichlet inverse of A000593. LINKS FORMULA G.f. A(x) satisfies: A(x) = x - Sum_{k>=2} A000593(k) * A(x^k). Dirichlet g.f.: 1 / (zeta(s) * zeta(s-1) * (1 - 2^(1-s))). a(1) = 1; a(n) = -Sum_{d|n, d

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Last modified January 21 13:55 EST 2020. Contains 331113 sequences. (Running on oeis4.)