A007135 - OEIS

A007135

Number of symmetry sites in all planted 1,3-trees with 2n nodes.
(Formerly M3283)

0, 1, 1, 4, 6, 15, 30, 74, 160, 379, 867, 2057, 4817, 11465, 27214, 65102, 155753, 374208, 900073, 2170500, 5240723, 12676162, 30697119, 74435204, 180679171

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

REFERENCES

Bailey, C. K.; Palmer, E. M.; Kennedy, J. W.; Points by degree and orbit size in chemical trees. II. Discrete Appl. Math. 5 (1983), no. 2, 157-164.

Bailey, C. K.; Fundamental orbits. Proceedings of the second West Coast conference on combinatorics, graph theory and computing (Eugene, Ore., 1983). Congr. Numer. 41 (1984), 149-152.

R. W. Robinson, personal communication.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=1..25.

Index entries for sequences related to rooted trees

Index entries for sequences related to trees

CROSSREFS

Sequence in context: A254325 A351145 A034299 * A294070 A073603 A064910

Adjacent sequences: A007132 A007133 A007134 * A007136 A007137 A007138

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved