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A127992
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Number of distinct prime factors of 2*n^3 - 2*n + 9.
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4
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1, 2, 2, 2, 2, 3, 2, 2, 3, 3, 2, 3, 2, 2, 2, 3, 2, 2, 2, 2, 2, 3, 4, 2, 3, 3, 3, 3, 3, 3, 2, 4, 3, 2, 2, 3, 3, 2, 3, 2, 3, 2, 3, 4, 3, 2, 3, 2, 4, 3, 4, 3, 2, 2, 3, 2, 2, 4, 2, 3, 4, 3, 3, 3, 4, 3, 2, 2, 2, 3, 3, 4, 3, 3, 4, 3, 3, 4, 4, 2, 2, 2, 3, 3, 3, 4, 3, 4, 2, 3, 2, 2, 3, 3, 3, 2, 4, 3, 2, 3, 4, 2, 3, 2, 4
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OFFSET
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1,2
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COMMENTS
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All numbers generated by the irreducible polynomial 2n^3 - 2n + 9 (A127989) are odd multiples of 3.
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LINKS
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FORMULA
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MATHEMATICA
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a = {}; Do[AppendTo[a, 2n^3 - 2n + 9], {n, 1, 300}]; b = {}; Do[c = FactorInteger[a[[n]]]; d = Length[c]; AppendTo[b, d], {n, 1, Length[a]}]; b
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PROG
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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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