OFFSET
0,7
REFERENCES
J. H. Conway, R. T. Curtis, S. P. Norton, R. A. Parker and R. A. Wilson, ATLAS of Finite Groups. Oxford Univ. Press, 1985 [for best online version see https://oeis.org/wiki/Welcome#Links_to_Other_Sites], p. 181. There is a typo in the table: the second line for vectors of type 11 should read u_3 + 2 v_4 (w_3).
J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, 3rd. ed., 1993. Tables 4.13 and 4.14.
EXAMPLE
a(2) = 1 since the group acts transitively on the 196560 minimal vectors (which have norm 4).
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Jan 11 2019
STATUS
approved