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A036363
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Line-labeled 2-trees with n nodes.
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0
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1, 30, 2940, 612360, 221371920, 123506903520, 98513415000000, 106466143825641600, 149822417112092524800, 266259578976734741798400, 583256031964344606759091200, 1544112027465820312500000000000, 4860420955731492909364541975040000
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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3,2
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REFERENCES
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F. Harary and E. Palmer, Graphical Enumeration, (1973), p. 30, Problem 1.13(c).
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LINKS
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MAPLE
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[ seq((2*n-3)!*(2*n-3)^(n-4)/(2*(n-2)!), n=3..20) ];
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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