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A341880
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Number of ordered factorizations of n into 4 factors > 1.
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3
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1, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 6, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 4, 0, 4, 0, 0, 0, 12, 0, 0, 0, 10, 0, 0, 0, 0, 0, 0, 0, 28, 0, 0, 0, 0, 0, 0, 0, 16, 1, 0, 0, 12, 0, 0, 0, 4, 0, 12, 0, 0, 0, 0, 0, 40, 0, 0, 0, 6, 0, 0, 0, 4, 0, 0, 0, 28, 0, 0, 0, 16
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OFFSET
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16,9
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LINKS
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FORMULA
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Dirichlet g.f.: (zeta(s) - 1)^4.
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MAPLE
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b:= proc(n) option remember; series(x*(1+add(b(n/d),
d=numtheory[divisors](n) minus {1, n})), x, 5)
end:
a:= n-> coeff(b(n), x, 4):
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MATHEMATICA
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b[n_] := b[n] = Series[x*(1 + Sum[b[n/d],
{d, Divisors[n] ~Complement~ {1, n}}]), {x, 0, 5}];
a[n_] := Coefficient[b[n], x, 4];
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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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