A283824 Number of unlabeled (and unrooted) trees on n nodes having a node that is both a center and a centroid.

1, 1, 0, 1, 1, 2, 2, 6, 7, 20, 27, 83, 126

Offset: 0

Author

N. J. A. Sloane, Mar 19 2017

Keywords

• nonn
• more

Comments

In view of the errors in the second line of the table (compare A000676 and A283823), the entries a(11)=83 and a(12)=126 should be checked carefully.

Links

• Peter Steinbach, Field Guide to Simple Graphs, Volume 1, Part 17 (For Volumes 1, 2, 3, 4 of this book see A000088, A008406, A000055, A000664, respectively.)
• Peter Steinbach, Field Guide to Simple Graphs, Volume 3, Part 12 (For Volumes 1, 2, 3, 4 of this book see A000088, A008406, A000055, A000664, respectively.)

Crossrefs

Cf. A000676, A283823, A027416.