A001059 - OEIS

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A001059

Number of labeled heap ordered trees.

1, 1, 5, 59, 1263, 42713, 2094399, 140434335, 12340275539, 1375857855221, 189751578038547, 31714568837559539, 6316261763436325285, 1477890415844440910325, 401400487846091289175217 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	COMMENTS	`A standard heap ordered tree with n + 1 nodes is a finite rooted tree in which all the nodes except the root are labeled with the natural numbers between 1 and n, which satisfies the property that the labels of the children of a node are all larger than the label of the node.`
	LINKS	`Index entries for sequences related to trees` `R. L. Grossman R. G. Larson, Hopf Algebras of Heap Ordered Trees and Permutations, arXiv:0706.1327v3 [math.RA]`
	FORMULA	`zf"+f'=1/(1-f).` `a(n) = Sum_{k=0..n-1} binomial(n, k)^2a(k)a(n-k-1). - Vladeta Jovovic (vladeta(AT)eunet.rs), Oct 22 2005`
	CROSSREFS	`Sequence in context: A113055 A020468 A093946 * A120608 A143766 A132549` `Adjacent sequences: A001056 A001057 A001058 * A001060 A001061 A001062`
	KEYWORD	`nonn`
	AUTHOR	`Helmut Prodinger [ Helmut.Prodinger(AT)inria.fr ]`

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Last modified February 17 16:13 EST 2012. Contains 206050 sequences.