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A052142
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E.g.f.: exp(x/(1-4*x)^(1/2)).
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0
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1, 1, 5, 49, 697, 12881, 291901, 7823425, 241878449, 8469678817, 331194361141, 14301627569681, 675802760007145, 34681947121134769, 1920727213363900397, 114166002761833118881, 7248797582463164166241, 489621781318487529974465
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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REFERENCES
| R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see page 191.
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LINKS
| Vladimir Kruchinin, Compositae and their properties , arXiv:1103.2582
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FORMULA
| a(n)=n!*sum((sum(2^k*k/(n-m)*binomial(2*(n-m)-k-1,n-m-1)*binomial(k+m-1,m-1),k,1,n-m))/m!,m,1,n-1)+1; [From Kruchinin Vladimir (kru(AT)ie.tusur.ru), Sep 10 2010]
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MAPLE
| a(n):=n!*sum((sum(2^k*k/(n-m)*binomial(2*(n-m)-k-1, n-m-1)*binomial(k+m-1, m-1), k, 1, n-m))/m!, m, 1, n-1)+1; (for Maxima) [From Kruchinin Vladimir (kru(AT)ie.tusur.ru), Sep 10 2010]
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CROSSREFS
| Sequence in context: A112241 A116873 A089914 * A136729 A102773 A028575
Adjacent sequences: A052139 A052140 A052141 * A052143 A052144 A052145
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Jan 23 2000
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