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A052763
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A simple grammar.
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3
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0, 1, 4, 26, 188, 1499, 12628, 111064, 1006840, 9345761, 88371580, 848273424, 8244075700, 80959901281, 802137370804, 8008422811882, 80488941119484, 813703130213745, 8268866850613468, 84417609311862182
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| Number of rooted trees with 4-colored non-root nodes. (Christian G. Bower (bowerc(AT)usa.net), Sep 07 2002)
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LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 720
Index entries for sequences related to rooted trees
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MAPLE
| spec := [S, {B=Set(S), S=Prod(Z, B, B, B, B)}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
| Sequence in context: A052775 A137964 A107649 * A084211 A114496 A127086
Adjacent sequences: A052760 A052761 A052762 * A052764 A052765 A052766
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KEYWORD
| easy,nonn,eigen
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AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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