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A052799
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A simple grammar.
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0
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0, 0, 0, 0, 0, 0, 720, 5040, 36960, 302400, 2761920, 27941760, 310495680, 3760922880, 49324923648, 696388492800, 10530709862400, 169811234611200, 2908629247795200, 52738216760033280, 1009115747652096000
(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 757
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FORMULA
| E.g.f.: x^4*ln(-1/(-1+x))^2
Recurrence: {a(1)=0, a(2)=0, a(4)=0, a(3)=0, a(5)=0, a(6)=720, (-5*n^3+n^4+32*n-6*n^2+32)*a(n)+(9*n^2+5*n-2*n^3-42)*a(n+1)+(n^2-5*n+6)*a(n+2)}
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MAPLE
| spec := [S, {B=Cycle(Z), S=Prod(Z, Z, Z, Z, B, B)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
| Sequence in context: A053625 A052793 A179728 * A153760 A029574 A119540
Adjacent sequences: A052796 A052797 A052798 * A052800 A052801 A052802
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KEYWORD
| easy,nonn
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AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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