1,2

J. H. Conway, R. T. Curtis, S. P. Norton, R. A. Parker and R. A. Wilson, ATLAS of Finite Groups. Oxford Univ. Press, 1985, 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.

T. D. Noe, Table of n, a(n) for n=1..20

2^(n*(n-1)) * (2^n - 1) * product( 2^(2*i)-1, i=1..n-1).

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:

Cf. A003923.

Sequence in context: A141475 A134374 A159423 this_sequence A067584 A146521 A159431

Adjacent sequences: A001305 A001306 A001307 this_sequence A001309 A001310 A001311

nonn,easy

N. J. A. Sloane (njas(AT)research.att.com).