id:A082989 - OEIS Search Results

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Number of ordered trees with n edges and having no root-to-leaf branches.

+0
4

1, 0, 0, 1, 4, 13, 42, 139, 470, 1616, 5632, 19852, 70654, 253559, 916558, 3334211, 12197142, 44842184, 165597008, 613991206, 2284809072, 8530458154, 31945128628, 119960276246, 451621453764, 1704240175868, 6445111657272 (list; graph; listen)

	OFFSET	`0,5`
	FORMULA	`a(n)=2sum((-1)^j*(j+2)binomial(2n-3-2j, n), j=0..floor((n-3)/2))/(n+1); g.f.= 2(1-z)/[1+z+(1-z)sqrt(1-4z)]`
	CROSSREFS	`Sequence in context: A022029 A010900 A070031 this_sequence A149425 A047144 A072307` `Adjacent sequences: A082986 A082987 A082988 this_sequence A082990 A082991 A082992`
	KEYWORD	`nonn`
	AUTHOR	`Emeric Deutsch (deutsch(AT)duke.poly.edu), May 29 2003`

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Last modified December 10 00:48 EST 2009. Contains 170565 sequences.

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