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Search: id:A052804
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| A052804 |
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A simple grammar: cycles of rooted cycles. |
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+0
1
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| 0, 0, 2, 3, 20, 90, 714, 5460, 54704, 580608, 7214040, 96932880, 1452396912, 23507621280, 414102201408, 7827185489760, 158757800613120, 3429996441661440, 78775916315263488, 1914627403408320000
(list; graph; listen)
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OFFSET
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0,3
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LINKS
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INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 765
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FORMULA
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G.f.: ln(-1/(-1+ln(-1/(-1+x))*x))
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MAPLE
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spec := [S, {B=Prod(C, Z), C=Cycle(Z), S=Cycle(B)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
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Sequence in context: A087301 A007113 A066166 this_sequence A125763 A042441 A128977
Adjacent sequences: A052801 A052802 A052803 this_sequence A052805 A052806 A052807
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KEYWORD
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easy,nonn
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AUTHOR
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encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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