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Search: id:A084357
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| A084357 |
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Number of sets of sets of lists. |
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+0
4
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| 1, 1, 4, 23, 171, 1552, 16583, 203443, 2813660, 43258011, 731183365, 13466814110, 268270250977, 5744515120489, 131525839441428, 3205279987587275, 82812074976214547, 2260364854328771548, 64979726427408468055, 1961976154991285214707
(list; graph; listen)
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OFFSET
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0,3
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REFERENCES
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T. S. Motzkin, Sorting numbers ...: for a link to this paper see A000262.
T. S. Motzkin, Sorting numbers for cylinders and other classification numbers, in Combinatorics, Proc. Symp. Pure Math. 19, AMS, 1971, pp. 167-176.
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LINKS
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T. D. Noe, Table of n, a(n) for n=0..100
K. A. Penson, P. Blasiak, G. Duchamp, A. Horzela and A. I. Solomon, Hierarchical Dobinski-type relations via substitution and the moment problem [J. Phys. A 37 (2004), 3475-3487]
K. A. Penson, P. Blasiak, G. Duchamp, A. Horzela and A. I. Solomon, Hierarchical Dobinski-type relations via substitution and the moment problem
N. J. A. Sloane and Thomas Wieder, The Number of Hierarchical Orderings, Order 21 (2004), 83-89.
P. Flajolet and R. Sedgewick, Analytic Combinatorics, 2009; see page 139
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FORMULA
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E.g.f.: exp(exp(x/(1-x))-1). Lah transform of Bell numbers: Sum_{k=0..n} n!/k!*binomial(n-1, k-1)*Bell(k). - Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 28 2003
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MAPLE
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with(combstruct); SetSetSeqL := [T, {T=Set(S), S=Set(U, card >= 1), U=Sequence(Z, card >=1)}, labeled]; [seq(count(%, size=j), j=1..12)];
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CROSSREFS
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Row sums of A079005 and row sums of A088814.
Sequence in context: A158884 A053525 A113869 this_sequence A075729 A127131 A083355
Adjacent sequences: A084354 A084355 A084356 this_sequence A084358 A084359 A084360
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Jun 22 2003
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