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A007135 Number of symmetry sites in all planted 1,3-trees with 2n nodes.
(Formerly M3283)
0
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: A045907 A254325 A034299 * A294070 A073603 A064910

Adjacent sequences:  A007132 A007133 A007134 * A007136 A007137 A007138

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified November 14 19:59 EST 2019. Contains 329128 sequences. (Running on oeis4.)