A048802 - OEIS

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A048802

Number of labeled rooted trees of nonempty sets with n points. (Each node is a set of 1 or more points.)

1, 3, 16, 133, 1521, 22184, 393681, 8233803, 198342718, 5408091155, 164658043397, 5537255169582, 203840528337291, 8153112960102283, 352079321494938344, 16325961781591781401, 809073412162081974237 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	LINKS	`Index entries for sequences related to rooted trees` `INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 861`
	FORMULA	`E.g.f.: B(e^x-1) where B is e.g.f. of A000169.` `a(n) = Sum_{k=1..n} Stirling2(n, k)*k^(k-1). - Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 17 2003`
	CROSSREFS	`Cf. A036249, A038052.` `Cf. A058863, A052807.` `Sequence in context: A023998 A179119 A141628 * A119392 A129043 A182951` `Adjacent sequences: A048799 A048800 A048801 * A048803 A048804 A048805`
	KEYWORD	`nonn`
	AUTHOR	`Christian G. Bower (bowerc(AT)usa.net), Mar 15 1999.`

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Last modified February 16 16:51 EST 2012. Contains 205938 sequences.