A283827 Irregular triangle read by rows: T(n,k) = number of trees on n nodes with load k, n>=1, 1 <= k <= floor(n/2).

0, 1, 1, 1, 1, 1, 2, 1, 2, 3, 1, 3, 7, 1, 3, 9, 10, 1, 4, 12, 30, 1, 4, 18, 38, 45, 1, 5, 21, 64, 144, 1, 5, 27, 91, 217, 210

Offset

1,7

Comments

The load of a tree is the maximal branch weight from the centroid.

Links

Table of n, a(n) for n=1..37.

Peter Steinbach, Field Guide to Simple Graphs, Volume 3, Part 8 (For Volumes 1, 2, 3, 4 of this book see A000088, A008406, A000055, A000664, respectively.)

Example

Triangle begins:
  0,
  1,
  1,
  1, 1,
  1, 2,
  1, 2,  3,
  1, 3,  7,
  1, 3,  9, 10,
  1, 4, 12, 30,
  1, 4, 18, 38,  45,
  1, 5, 21, 64, 144,
  1, 5, 27, 91, 217, 210,
  ...

Crossrefs

Cf. A283826.

See also A000676, A000677, A027416, A102911.

Sequence in context: A110062 A144215 A254539 * A122087 A139642 A264744

Adjacent sequences: A283824 A283825 A283826 * A283828 A283829 A283830

Keyword

nonn,tabf,more

Author

N. J. A. Sloane, Mar 19 2017

Status

approved