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A307309
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Self-composition of the Dedekind psi function (A001615).
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2
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1, 6, 26, 99, 348, 1194, 4000, 13326, 44058, 144066, 462504, 1459194, 4545588, 14068554, 43450848, 134213808, 414692130, 1280610858, 3948172380, 12142365042, 37235047770, 113844652986, 347103133068, 1055610536520, 3202944247674, 9697395164616, 29298206343284
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OFFSET
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1,2
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LINKS
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FORMULA
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G.f.: g(g(x)), where g(x) = Sum_{k>=1} mu(k)^2*x^k/(1 - x^k)^2 is the g.f. of A001615.
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MATHEMATICA
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g[x_] := g[x] = Sum[MoebiusMu[k]^2 x^k/(1 - x^k)^2, {k, 1, 27}]; a[n_] := a[n] = SeriesCoefficient[g[g[x]], {x, 0, n}]; Table[a[n], {n, 27}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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