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A104353
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Sum of divisors of A104350(n).
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2
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1, 3, 12, 28, 168, 546, 4368, 9360, 28800, 148800, 1785600, 5401440, 75620160, 538793640, 2711348640, 5603453856, 100862169408, 303420079872, 6068401597440, 30380907997440, 213199354368000, 2362959510912000, 56711028261888000, 170288884313856000
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OFFSET
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1,2
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LINKS
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FORMULA
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MATHEMATICA
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DivisorSigma[1, FoldList[Times, Array[FactorInteger[#][[-1, 1]] &, 30]]] (* Amiram Eldar, Apr 08 2024 *)
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PROG
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(PARI) gpf(n) = {my(p = factor(n)[, 1]); p[#p]; }
a(n) = sigma(prod(k = 2, n, gpf(k))); \\ Amiram Eldar, Apr 08 2024
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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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