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A162884
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Half the difference between the larger and smaller term of the n-th amicable pair.
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3
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32, 13, 152, 272, 68, 56, 1155, 560, 6532, 32, 2025, 9009, 4490, 11835, 8775, 392, 5756, 13210, 2240, 2288, 9032, 2860, 42272, 40652, 55426, 21592, 8944, 8575, 5840, 1755, 34648, 38072, 33536, 38296, 4664, 57796, 35296, 30555, 10856, 41384, 88965, 22496
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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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EXAMPLE
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a(7)=1155 because the 7th pair of amicable numbers is 12285 and 14595; and (14595-12285)/2=1155.
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MAPLE
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read("transforms3") ; L002046 := BFILETOLIST("b002046.txt") : L002025 := BFILETOLIST("b002025.txt") : A066539 := proc(n) global L002046, L002025; op(n, L002046)-op(n, L002025) ; end:
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MATHEMATICA
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With[{s = PositionIndex@ Array[DivisorSigma[1, #] &, 10^6]}, Flatten@ Map[Differences, Apply[Join, Map[Function[n, Select[Subsets[Lookup[s, n], {2}], Total@ # == n &]], Sort@ Select[Keys@ s, Length@ Lookup[s, #] > 1 &]]]]/2] (* Michael De Vlieger, Oct 26 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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