id:A091486 - OEIS Search Results

Search: id:A091486

Displaying 1-1 of 1 results found.

page 1

Number of unlabeled rooted 2,3 cacti (triangular cacti with bridges).

+0
3

1, 1, 3, 7, 21, 60, 190, 600, 1977, 6589, 22408, 77050, 268178, 941599, 3333585, 11882427, 42615480, 153653039, 556664752, 2025330509, 7397242875, 27111563026, 99681629658, 367563272278, 1358945378906, 5036549490009 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`Also number of unlabeled involution rooted trees.`
	LINKS	`N. J. A. Sloane, Transforms` `Index entries for sequences related to cacti` `Index entries for sequences related to rooted trees`
	FORMULA	`Shifts left under transform T where Ta = EULER(E_1, 2(a)). E_1, 2(a) has g.f. A(x)+(A(x^2)+A(x)^2)/2.`
	CROSSREFS	`Adjacent sequences: A091483 A091484 A091485 this_sequence A091487 A091488 A091489` `Sequence in context: A091650 A096240 A035080 this_sequence A056779 A102877 A122983`
	KEYWORD	`nonn,eigen`
	AUTHOR	`Christian G. Bower (bowerc(AT)usa.net), Jan 14 2004`

page 1

Search completed in 0.002 seconds

Last modified October 13 20:18 EDT 2008. Contains 145016 sequences.

AT&T Labs Research