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A139466
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Smallest prime factor of n! + 2n - 1.
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4
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2, 5, 11, 31, 3, 17, 31, 3, 362897, 3628819, 3, 251, 5, 3, 93407, 200989, 3, 5, 211, 3, 199, 38189, 3, 314707, 7, 3, 2473, 5, 3, 98274048659069, 1447, 3, 5, 585341, 3, 61, 8150209692797, 3, 7, 131, 3, 193, 5, 3, 73, 7, 3, 5, 53, 3, 647, 151897, 3, 67801, 7001
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OFFSET
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1,1
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LINKS
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FORMULA
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MATHEMATICA
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a = {}; Do[AppendTo[a, n! + 2 n - 1], {n, 1, 40}]; b = {}; Do[c = FactorInteger[a[[n]]]; d = c[[1]]; AppendTo[b, d[[1]]], {n, 1, Length[a]}]; b (* Artur Jasinski *)
FactorInteger[#][[1, 1]] & /@ Table[n! + 2*n - 1, {n, 1, 18}] (* Amiram Eldar, Feb 05 2020 ()
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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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EXTENSIONS
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STATUS
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approved
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