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A272499
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Number of ordered set partitions of [n] with nondecreasing block sizes and maximal block size equal to nine.
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2
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1, 10, 165, 2200, 33605, 492492, 8018010, 131342640, 2321677930, 42349478600, 820275716546, 16515429370440, 350240612952230, 7731410818511380, 178693701272340540, 4296129057927296304, 107666415418378051950, 2801776425029317564400, 75741144900761549630850
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OFFSET
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9,2
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LINKS
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FORMULA
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E.g.f.: x^9 * Product_{i=1..9} (i-1)!/(i!-x^i).
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MAPLE
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b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
b(n, i-1)+`if`(i>n, 0, binomial(n, i)*b(n-i, i))))
end:
a:= n-> (k-> b(n, k) -b(n, k-1))(9):
seq(a(n), n=9..30);
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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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