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A034743
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a(n) = Sum_{d | n} mu(n/d) * Bell(d-1).
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2
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1, 0, 1, 4, 14, 50, 202, 872, 4138, 21132, 115974, 678514, 4213596, 27644234, 190899306, 1382957668, 10480142146, 82864865614, 682076806158, 5832742183906, 51724158235168, 474869816040776, 4506715738447322
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OFFSET
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1,4
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COMMENTS
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A kind of Dirichlet convolution of mu(n) with Bell numbers.
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LINKS
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MATHEMATICA
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a[n_] := Sum[MoebiusMu[n/d]*BellB[d - 1], {d, Divisors[n]}];
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PROG
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(PARI)
bell(n) = sum(k=0, n, stirling(n, k, 2));
a(n) = sumdiv(n, d, moebius(n/d) * bell(d-1)); \\ Andrew Howroyd, Apr 03 2017
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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