
COMMENTS

Let G_n be an nvertex simple graph, with a(G_n) automorphisms. Then l(G_n) = n!/a(G_n) is the number of labeled copies of G_n. So a(n) is the number of G_n for which n does not divide l(G_n).
For prime p, a(p) is the number of circulants of order p.
The number of circulants of order n is A049287(n).


REFERENCES

John P. McSorley, Smallest labelled class (and largest automorphism group) of a tree T_{s,t} and good labellings of a graph, preprint, (2016).
R. C. Read, R. J. Wilson, An Atlas of Graphs, Oxford Science Publications, Oxford University Press, (1998).
James Turner, Pointsymmetric graphs with a prime number of points, Journal of Combinatorial Theory, vol. 3 (1967), 136145.
