A003616 - OEIS

A003616

Symmetries in unrooted 4-trees on n+1 vertices.
(Formerly M0377)

1, 2, 2, 8, 28, 20, 43, 143, 249, 546, 1223, 2703, 8107, 18085, 44013, 114919, 327712, 800937, 2146066, 5827711, 15923828, 43886143, 121888966, 340209504, 955859391, 2700771322, 7652412896, 21784431688, 62248194140, 178463482459

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

OFFSET

1,2

REFERENCES

Kathleen A. McKeon, The expected number of symmetries in locally-restricted trees I, pp. 849-860 of Y. Alavi et al., eds., Graph Theory, Combinatorics and Applications. Wiley, NY, 2 vols., 1991.

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..30.

Kathleen A. McKeon, Letter to N. J. A. Sloane, July 25 1991

Kathleen A. McKeon, The expected number of symmetries in locally-restricted trees I, pp. 849-860 of Y. Alavi et al., eds., Graph Theory, Combinatorics and Applications. Wiley, NY, 2 vols., 1991. [Annotated scanned copy]

Index entries for sequences related to trees

CROSSREFS

Sequence in context: A372795 A287756 A287496 * A276657 A079895 A351512

Adjacent sequences: A003613 A003614 A003615 * A003617 A003618 A003619

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mira Bernstein

STATUS

approved