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A245862
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Number of preferential arrangements of n labeled elements such that the minimal number of elements per rank equals 9.
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2
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1, 0, 0, 0, 0, 0, 0, 0, 0, 48620, 184756, 335920, 587860, 994840, 1634380, 2615008, 4085950, 6249100, 227882805150, 1914150638400, 10597377540750, 42894094729200, 150967391072550, 488846715676800, 1495608303532200, 4389524294884872, 12479799500904120
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OFFSET
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9,10
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LINKS
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FORMULA
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E.g.f.: 1/(1-Sum_{j>=9} x^j/j!) - 1/(1-Sum_{j>=10} x^j/j!).
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MAPLE
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b:= proc(n, k) option remember; `if`(n=0, 1,
add(b(n-j, k)*binomial(n, j), j=k..n))
end:
a:= n-> b(n, 9) -b(n, 10):
seq(a(n), n=9..40);
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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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