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A052769
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A simple grammar.
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0
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0, 0, 0, 0, 0, 120, 720, 2940, 10080, 31248, 90720, 251460, 673200, 1753752, 4468464, 11176620, 27518400, 66838560, 160422336, 381014676, 896518800
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,6
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LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 726
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FORMULA
| E.g.f.: x^3*exp(x)^2-2*x^3*exp(x)+x^3
Recurrence: {a(1)=0, a(2)=0, a(4)=0, a(3)=0, (2*n^2+6*n+4)*a(n)+(-3*n^2+12)*a(n+1)+(-3*n+n^2+2)*a(n+2), a(5)= 120}
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MAPLE
| spec := [S, {B=Set(Z, 1 <= card), S=Prod(Z, Z, Z, B, B)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
| Sequence in context: A039688 A005820 A052787 * A179724 A052766 A052627
Adjacent sequences: A052766 A052767 A052768 * A052770 A052771 A052772
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KEYWORD
| easy,nonn
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AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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