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A074740
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a(n) = n!*2^(n-1)/Product_{k=1..n} tau(k) where tau = A000005.
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0
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1, 2, 6, 16, 80, 240, 1680, 6720, 40320, 201600, 2217600, 8870400, 115315200, 807206400, 6054048000, 38745907200, 658680422400, 3952082534400, 75089568153600, 500597121024000, 5256269770752000, 57818967478272000, 1329836252000256000, 7979017512001536000
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OFFSET
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1,2
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COMMENTS
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Appears to be an integer for n >= 1.
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LINKS
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FORMULA
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PROG
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(PARI) a(n) = n!*2^(n-1)/prod(k=1, n, numdiv(k)); \\ Michel Marcus, Jan 09 2021
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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