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Search: id:A036768
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| A036768 |
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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, 132, 428, 1421, 4807, 16510, 57421, 201824, 715768, 2558167, 9204651, 33315919, 121218195, 443107245, 1626546453, 5993256280, 22158739970, 82182744284, 305670888560, 1139892935454, 4261095044346, 15964169665031
(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 := 6; [ 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/polcyclo(7)+O(x^(n+2))), n+1)) (from R. Stephan)
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CROSSREFS
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Sequence in context: A061922 A024175 A054393 this_sequence A058094 A080938 A054394
Adjacent sequences: A036765 A036766 A036767 this_sequence A036769 A036770 A036771
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KEYWORD
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nonn
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AUTHOR
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njas
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