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Search: id:A127990
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| A127990 |
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Largest prime factor of 2n^3 - 2n + 9. |
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+0
4
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| 3, 7, 19, 43, 83, 13, 227, 113, 23, 17, 883, 37, 1459, 1823, 2243, 389, 11, 431, 13, 5323, 6163, 373, 89, 9203, 103, 83, 257, 443, 439, 367, 19843, 73, 647, 26183, 9521, 797, 1607, 36559, 3593, 42643, 2417, 49367, 1709, 53, 173, 7207, 1609, 73699, 163, 7573
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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All numbers generated by the irreducible polynomial 2n^3 - 2n + 9 (A127989) are odd and composite. Smallest prime factor A127991, number of prime factors A127992
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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 = c[[Length[c]]]; AppendTo[b, d[[1]]], {n, 1, Length[a]}]; b (*Artur Jasinski*)
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CROSSREFS
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Cf. A127989, A127991, A127992.
Sequence in context: A090689 A145476 A126938 this_sequence A055622 A075900 A069051
Adjacent sequences: A127987 A127988 A127989 this_sequence A127991 A127992 A127993
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KEYWORD
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nonn
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AUTHOR
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Artur Jasinski (grafix(AT)csl.pl), Feb 10 2007
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