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A195209
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Sum of even divisors of !n.
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0
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0, 0, 0, 2, 0, 72, 0, 2704, 0, 268128, 0, 17621496, 0, 4974281208, 0, 549790303712, 0, 245357774621280, 0, 67684833350266496, 0, 36434223374991414336, 0, 10781900341537812480000, 0, 14585451990785851336761600
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OFFSET
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0,4
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LINKS
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EXAMPLE
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a(7) = 2704 because the divisors of !7 = 1854 are {1, 2, 3, 6, 9, 18, 103, 206, 309, 618, 927, 1854}, and the sum of the 6 even divisors 2, 6, 18, 206, 618 and 1854 is 2704.
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MATHEMATICA
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Table[Total[Select[Divisors[Subfactorial[n]], EvenQ[ # ]&]], {n, 0, 25}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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