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A052794
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A simple grammar.
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1
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0, 0, 0, 0, 0, 0, 720, 2520, 13440, 90720, 725760, 6652800, 68428800, 778377600, 9686476800, 130767436800, 1902071808000, 29640619008000, 492490285056000, 8688935743488000, 162193467211776000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,7
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LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 751
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FORMULA
| E.g.f.: x^5*ln(-1/(-1+x))
Recurrence: {a(1)=0, a(2)=0, a(4)=0, a(3)=0, a(5)=0, a(6)=720, (-n^2+4*n+5)*a(n)+(-4+n)*a(n+1)}
0
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MAPLE
| spec := [S, {B=Cycle(Z), S=Prod(Z, Z, Z, Z, Z, B)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
| Sequence in context: A000805 A112530 A052800 * A096933 A061299 A167563
Adjacent sequences: A052791 A052792 A052793 * A052795 A052796 A052797
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KEYWORD
| easy,nonn
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AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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