A059221 - OEIS

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A059221

Number of 3-bead necklaces where each bead is an unlabeled rooted tree, by total number of nodes.

1, 1, 2, 4, 8, 18, 43, 103, 255, 642, 1640, 4242, 11096, 29278, 77882, 208589, 562056, 1522606, 4144521, 11329608, 31090910, 85618848, 236530942, 655344579, 1820585313, 5070138554, 14151907583, 39584395796, 110938500821, 311481097178 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	CROSSREFS	`See A058855 (the 6-bead analogue) for details.` `Sequence in context: A024428 A049075 A052327 * A193617 A114203 A100132` `Adjacent sequences: A059218 A059219 A059220 * A059222 A059223 A059224`
	KEYWORD	`nonn`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com), Jan 18 2001`

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Last modified February 16 19:40 EST 2012. Contains 205946 sequences.