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A283824 Number of unlabeled (and unrooted) trees on n nodes having a node that is both a center and a centroid. 0
1, 1, 0, 1, 1, 2, 2, 6, 7, 20, 27, 83, 126 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

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

Table of n, a(n) for n=0..12.

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.

Sequence in context: A060303 A099577 A268500 * A106168 A106166 A101343

Adjacent sequences:  A283821 A283822 A283823 * A283825 A283826 A283827

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, Mar 19 2017

STATUS

approved

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Last modified August 24 22:41 EDT 2019. Contains 326314 sequences. (Running on oeis4.)