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Search: id:A052740
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| A052740 |
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A simple context-free grammar in a labeled universe. |
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+0
1
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| 0, 1, 2, 12, 144, 2400, 50400, 1290240, 39070080, 1365154560, 54047347200, 2391175987200, 116918542540800, 6260970517401600, 364413626331955200, 22906448213096448000, 1546480919558615040000, 111605770820457897984000
(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 696
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FORMULA
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E.g.f.: RootOf(-_Z+_Z^4+_Z^2+x)
Recurrence: {a(1)=1, a(0)=0, a(2)=2, a(3)=12, (576*n-9216*n^3-2688*n^2+192-6144*n^4)*a(n)+(-6400*n^3-23112-36480*n^2-54608*n)*a(n+1)+(13184*n+17772+896*n^2)*a(n+2)+(-14800-5176*n)*a(n+3)+1147*a(n+4)}
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MAPLE
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spec := [S, {C=Prod(B, B), S=Union(B, Z, C), B=Prod(S, S)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
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Sequence in context: A087800 A009747 A067601 this_sequence A052742 A035049 A010790
Adjacent sequences: A052737 A052738 A052739 this_sequence A052741 A052742 A052743
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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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