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A052792
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A simple grammar.
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0
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0, 0, 0, 0, 0, 0, 720, 10080, 87360, 604800, 3674160, 20512800, 108044640, 545688000, 2671036368, 12763951200, 59856451200, 276499641600, 1261691128944, 5699120476320, 25525119703200
(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 749
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FORMULA
| E.g.f.: x^2*exp(x)^4-4*x^2*exp(x)^3+6*x^2*exp(x)^2-4*exp(x)*x^2+x^2
Recurrence: {a(1)=0, a(2)=0, a(4)=0, a(3)=0, a(5)=0, a(6)=720, (1200*n+840*n^2+240*n^3+576+24*n^4)*a(n)+(1200-50*n^4+100*n-850*n^2-400*n^3)*a(n+1)+(210*n^3+175*n^2+35*n^4-420*n)*a(n+2)+(10*n^2-40*n^3+40*n-10*n^4)*a(n+3)+(-n^2+n^4-2*n+2*n^3)*a(n+4)}
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MAPLE
| spec := [S, {B=Set(Z, 1 <= card), S=Prod(Z, Z, B, B, B, B)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
| Sequence in context: A052784 A052786 A187192 * A052790 A052521 A052785
Adjacent sequences: A052789 A052790 A052791 * A052793 A052794 A052795
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KEYWORD
| easy,nonn
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AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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