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A337257
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Number of even divisors of n!.
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2
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0, 0, 1, 2, 6, 12, 24, 48, 84, 140, 240, 480, 720, 1440, 2376, 3696, 5040, 10080, 13824, 27648, 38880, 57600, 91200, 182400, 232320, 325248, 510048, 649152, 882000, 1764000, 2246400, 4492800, 5356800, 7618560, 11796480, 15925248
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OFFSET
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0,4
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LINKS
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FORMULA
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EXAMPLE
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The a(2) = 1 through a(5) = 12 divisors:
2 2 2 2
6 4 4
6 6
8 8
12 10
24 12
20
24
30
40
60
120
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MATHEMATICA
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Table[Length[Select[Divisors[n!], EvenQ]], {n, 0, 15}]
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PROG
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(PARI) a(n) = sumdiv(n!, d, !(d%2)); \\ Michel Marcus, Aug 24 2020
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CROSSREFS
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A000265 gives the maximum odd divisor of n.
Factorial numbers: A000142, A022559, A027423 (divisors), A048656, A071626, A076716 (factorizations), A325272, A325273, A325617, A336414, A336498.
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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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