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A264082
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Total number of inversions in all set partitions of [n].
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4
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0, 0, 0, 1, 10, 74, 504, 3383, 23004, 160444, 1154524, 8594072, 66243532, 528776232, 4369175522, 37343891839, 329883579768, 3008985817304, 28312886239136, 274561779926323, 2741471453779930, 28159405527279326, 297291626845716642, 3223299667111201702
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OFFSET
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0,5
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COMMENTS
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Each set partition is written as a sequence of blocks, ordered by the smallest elements in the blocks.
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LINKS
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FORMULA
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EXAMPLE
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a(3) = 1: one inversion in 13|2.
a(4) = 10: one inversion in each of 124|3, 13|24, 13|2|4, 1|24|3, and two inversions in each of 134|2, 14|23, 14|2|3.
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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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