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A350135
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Number of endofunctions on [2n] whose smallest connected component has size n.
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2
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1, 1, 27, 2890, 705740, 310181886, 215071984512, 216357598418676, 298018065222408960, 538758820820128412790, 1237604585414359892787200, 3521561770316172974098259916, 12159265179096745219044911480832, 50086112147669900240287215353718700, 242646275221231775443338250567758643200
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OFFSET
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0,3
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COMMENTS
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a(0) = 1 by convention.
Number of endofunctions on [2n] with two connected components of size n.
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LINKS
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FORMULA
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EXAMPLE
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a(1) = 1: 12.
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MAPLE
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a:= n-> `if`(n=0, 1, add(n^(n-j)*(n-1)!/(n-j)!, j=1..n)^2*binomial(2*n, n)/2):
seq(a(n), n=0..14);
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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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