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

Offset: 0

Author

N. J. A. Sloane, Jan 18 2001

Keywords

• nonn

Crossrefs

See A058855 (the 6-bead analog) for details.