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 A328721 Dirichlet g.f.: Product_{p prime, k>=1} (1 + p^(-s*k)) / (1 - p^(-s*k)). 0
 1, 2, 2, 4, 2, 4, 2, 8, 4, 4, 2, 8, 2, 4, 4, 14, 2, 8, 2, 8, 4, 4, 2, 16, 4, 4, 8, 8, 2, 8, 2, 24, 4, 4, 4, 16, 2, 4, 4, 16, 2, 8, 2, 8, 8, 4, 2, 28, 4, 8, 4, 8, 2, 16, 4, 16, 4, 4, 2, 16, 2, 4, 8, 40, 4, 8, 2, 8, 4, 8, 2, 32, 2, 4, 8, 8, 4, 8, 2, 28 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Dirichlet convolution of A000688 with A050361. LINKS FORMULA a(n) = Sum_{d|n} A000688(n/d) * A050361(d). If n = Product (p_j^k_j) then a(n) = Product (A015128(k_j)). MATHEMATICA Table[DivisorSum[n, (Times @@ PartitionsP[Last /@ FactorInteger[n/#]]) (Times @@ PartitionsQ[Last /@ FactorInteger[#]]) &], {n, 1, 80}] CROSSREFS Cf. A000688, A015128, A050361. Sequence in context: A085191 A188581 A318316 * A165872 A061142 A318312 Adjacent sequences:  A328718 A328719 A328720 * A328722 A328723 A328724 KEYWORD nonn,mult AUTHOR Ilya Gutkovskiy, Oct 26 2019 STATUS approved

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Last modified August 11 06:20 EDT 2020. Contains 336422 sequences. (Running on oeis4.)