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Search: id:A036767
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| A036767 |
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Number of rooted trees with a degree constraint. |
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+0
1
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| 1, 1, 2, 5, 14, 42, 131, 421, 1385, 4642, 15795, 54418, 189454, 665471, 2355510, 8393461, 30084695, 108394449, 392356788, 1426137550, 5203211200, 19048447855, 69951072700, 257609070810, 951172531880, 3520465229446, 13058843476526
(list; graph; listen)
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OFFSET
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0,3
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REFERENCES
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L. Takacs, Enumeration of rooted trees and forests, Math. Scientist 18 (1993), 1-10, esp. Eq. (6).
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LINKS
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Index entries for sequences related to rooted trees
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MAPLE
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r := 5; [ 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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PROGRAM
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(PARI) a(n)=if(n<0, 0, polcoeff(serreverse(x/sum(k=0, 5, x^k)+O(x^(n+2))), n+1)) (from R. Stephan)
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CROSSREFS
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Sequence in context: A080937 A054392 A006930 this_sequence A061922 A162746 A148329
Adjacent sequences: A036764 A036765 A036766 this_sequence A036768 A036769 A036770
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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