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A052891
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A simple grammar.
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0
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0, 1, 2, 5, 16, 56, 217, 876, 3686, 15903, 70103, 314042, 1426076, 6548060, 30352695, 141837086, 667469159, 3160370217, 15045244375, 71970393570, 345766441537
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 867
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MAPLE
| spec := [S, {C=Prod(Z, B), S=Set(C, 1 <= card), B=Sequence(S)}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
| Sequence in context: A141201 A149977 A147771 * A052815 A195931 A082789
Adjacent sequences: A052888 A052889 A052890 * A052892 A052893 A052894
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KEYWORD
| easy,nonn
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AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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