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A119794
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a(n) is the product of the positive integers each of which is <= n and is divisible by exactly one prime dividing n (but is coprime to every other prime dividing n). (a(1) = 1).
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4
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1, 2, 3, 8, 5, 24, 7, 384, 162, 1920, 11, 17280, 13, 322560, 97200, 10321920, 17, 58060800, 19, 1393459200, 51438240, 40874803200, 23, 536481792000, 375000, 25505877196800, 7142567040, 535623421132800, 29, 439378587648000, 31
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OFFSET
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1,2
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LINKS
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EXAMPLE
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12 is divisible by 2 and 3. The positive integers which are <= 12 and which are divisible by 2 or 3, but not by both 2 and 3, are: 2, 3, 4, 8, 9, 10. a(12) = the product of these integers, which is 17280.
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MATHEMATICA
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Table[Times @@ Select[Range@ n, Function[k, Total@ Boole@ Map[Divisible[k, #] &, FactorInteger[n][[All, 1]]] == 1]], {n, 31}] (* Michael De Vlieger, Oct 01 2017 *)
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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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