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A001308
Order of Chevalley group D_n (2).
3
1, 36, 20160, 174182400, 23499295948800, 50027557148216524800, 1691555775522928280469504000, 911666827031785075278550369566720000, 7846393898179181843651374899795632943267840000
OFFSET
1,2
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. xvi.
H. S. M. Coxeter and W. O. J. Moser, Generators and Relations for Discrete Groups, 4th ed., Springer-Verlag, NY, reprinted 1984, p. 131.
FORMULA
a(n) = 2^(n*(n-1)) * (2^n - 1) * Product_{i=1..n-1} (2^(2*i) - 1).
MAPLE
for m from 0 to 25 do N:=2^(m*(m-1))*mul( 4^i-1, i=1..m-1)*(2^m-1); lprint(N); od:
CROSSREFS
Cf. A003923.
Sequence in context: A271337 A203329 A271338 * A067584 A308423 A146521
KEYWORD
nonn,easy
STATUS
approved