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Search: id:A000775
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| A000775 |
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n! * (n + 1 + 2*Sum[k=1...n, 1/k]). |
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+0
1
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| 1, 4, 12, 46, 220, 1268, 8568, 66456, 582048, 5681952, 61174080, 720089280, 9199906560, 126783809280, 1874605662720, 29601115891200, 497155992883200, 8849184886886400, 166399076525875200, 3296032301811916800
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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J. R. Stembridge, Some combinatorial aspects of reduced words in finite Coxeter groups. Trans. Amer. Math. Soc. 349 (1997), no. 4, 1285-1332.
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FORMULA
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E.g.f.: x/(1-x)+ln(1-x)^2. - Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 02 2003
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CROSSREFS
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Similar to A000774.
Sequence in context: A149373 A151464 A101225 this_sequence A149374 A149375 A035310
Adjacent sequences: A000772 A000773 A000774 this_sequence A000776 A000777 A000778
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KEYWORD
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nonn,new
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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Incorrect formula deleted Mark (hoeij(AT)math.fsu.edu), Nov 11 2009
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