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A343493
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a(n) = 1 - Sum_{d|n, d < n} a(d - 1).
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1
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1, 1, 0, 0, -1, 0, -1, 0, -1, 0, 0, 0, -1, 0, 0, 1, -1, 0, 0, 0, 0, 1, -1, 0, -1, 1, 0, 1, 0, 0, 0, 0, -2, 0, 0, 2, 0, 0, -1, 1, 0, 0, 0, 0, -2, 2, 0, 0, -2, 1, 1, 1, -1, 0, 0, 1, -1, 0, -1, 0, 0, 0, -1, 2, -2, 2, 0, 0, 0, 1, 1, 0, -2, 0, -1, 2, -1, 1, 0, 0, -2, 1, -1, 0, -1, 2, -1, 0, -2, 0, 3
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OFFSET
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0,33
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LINKS
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FORMULA
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G.f. A(x) satisfies: A(x) = 1 / (1 - x) - x^2 * A(x^2) - x^3 * A(x^3) - x^4 * A(x^4) - ...
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MATHEMATICA
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a[n_] := a[n] = 1 - Sum[If[d < n, a[d - 1], 0], {d, Divisors[n]}]; Table[a[n], {n, 0, 90}]
nmax = 90; A[_] = 0; Do[A[x_] = 1/(1 - x) - Sum[x^k A[x^k], {k, 2, nmax}] + O[x]^(nmax + 1) //Normal, nmax + 1]; CoefficientList[A[x], x]
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PROG
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(Python)
from functools import lru_cache
from sympy import divisors
@lru_cache(maxsize=None)
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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