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A231167
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a(1) = a(2) = 0, for n>=3: (sum of non-divisors of n) modulo (number of non-divisors of n).
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4
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0, 0, 0, 0, 0, 1, 0, 1, 2, 1, 0, 2, 0, 1, 8, 6, 0, 0, 0, 0, 12, 1, 0, 0, 8, 1, 16, 20, 0, 19, 0, 23, 20, 1, 24, 8, 0, 1, 24, 26, 0, 25, 0, 32, 21, 1, 0, 26, 18, 38, 32, 38, 0, 31, 40, 36, 36, 1, 0, 30, 0, 1, 31, 15, 48, 37, 0, 50, 44, 47, 0, 33, 0, 1, 35, 56
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OFFSET
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1,9
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COMMENTS
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a(n) = 0 for n = 1, 2 and numbers from A140826.
a(n) = 1 for numbers of form 2*p (p=prime) from A100484 and other numbers, e.g. 8 and 13456 are only numbers n < 10^5 which are not of form 2*p with a(n) = 1.
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LINKS
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FORMULA
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EXAMPLE
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MATHEMATICA
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ndn[n_]:=Module[{nd=Complement[Range[n], Divisors[n]]}, Mod[Total[ nd], Length[ nd]]]; Join[{0, 0}, Array[ndn, 80, 3]] (* Harvey P. Dale, Apr 11 2022 *)
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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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