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Search: id:A052124
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| A052124 |
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E.g.f.: exp(-2x)/(1-x)^3. |
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+0
2
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| 1, 1, 4, 16, 88, 568, 4288, 36832, 354688, 3781504, 44199424, 561823744, 7714272256, 113769309184, 1793341407232, 30085661765632, 535170830467072, 10060645294440448, 199287423535808512, 4148644277780217856
(list; graph; listen)
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OFFSET
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0,3
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REFERENCES
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R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Problem 5.64(b).
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FORMULA
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a(n) = n*a(n-1)+2*(n-1)*a(n-2). - Detlef Pauly (dettodet(AT)yahoo.de), Sep 22 2003
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MAPLE
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A052124 := proc(n) option remember; if n <=1 then 1 else n*A052124(n-1)+2*(n-1)*A052124(n-2); fi; end; (from Detlef Pauly)
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CROSSREFS
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Cf. A052127.
Sequence in context: A165964 A005618 A005495 this_sequence A013030 A124962 A009568
Adjacent sequences: A052121 A052122 A052123 this_sequence A052125 A052126 A052127
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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), Jan 23 2000
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