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A373549
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a(n) is the parity of the n-th powerful number.
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3
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1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1
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OFFSET
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1
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LINKS
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FORMULA
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Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = (2 - sqrt(2))/(3 - sqrt(2)) = 0.3693980625... .
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MATHEMATICA
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Mod[Select[Range[5000], # == 1 || Min[FactorInteger[#][[;; , 2]]] > 1 &], 2]
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PROG
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(PARI) lista(kmax) = for(k = 1, kmax, if(ispowerful(k), print1(k % 2, ", ")));
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CROSSREFS
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Characteristic function of A363189.
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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