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A036769
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Number of rooted trees with a degree constraint.
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2
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1, 1, 2, 5, 14, 42, 132, 429, 1429, 4852, 16730, 58422, 206192, 734332, 2635680, 9524301, 34622207, 126520393, 464517300, 1712650520, 6338433840, 23538973950, 87690410580, 327611738790, 1227178265182, 4607940112396, 17341126763366
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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REFERENCES
| L. Takacs, Enumeration of rooted trees and forests, Math. Scientist 18 (1993), 1-10, esp. Eq. (6).
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LINKS
| Index entries for sequences related to rooted trees
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MAPLE
| r := 7; [ seq((1/n)*add( (-1)^j*binomial(n, j)*binomial(2*n-2-j*(r+1), n-1), j=0..floor((n-1)/(r+1))), n=1..30) ]; end;
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PROG
| (PARI) a(n)=if(n<0, 0, polcoeff(serreverse(x/sum(k=0, 7, x^k)+O(x^(n+2))), n+1)) (from R. Stephan)
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CROSSREFS
| Sequence in context: A058094 A080938 A054394 * A033191 A168491 A115140
Adjacent sequences: A036766 A036767 A036768 * A036770 A036771 A036772
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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