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A232663
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Number of permutations of order n such that no proper partial sum is zero modulo n.
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1
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1, 1, 2, 12, 48, 280, 2040, 16632, 139440, 1404864, 15405120, 185361792, 2380777344, 33252800256, 495338598144
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OFFSET
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1,3
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LINKS
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FORMULA
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For n>1, a(n) = A232664(n) * (n-1-(n mod 2)).
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EXAMPLE
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For n=4, in permutation (1,2,4,3), proper partial sums are 1, 1+2=3, 1+2+4=7, neither of which is zero modulo n. The number of such permutations is a(4)=12.
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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