2,1

H. S. M. Coxeter and W. O. J. Moser, Generators and Relations for Discrete Groups, 4th ed., Springer-Verlag, NY, reprinted 1984, p. 131.

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.

Sequence in context: A105299 A094232 A132185 this_sequence A003935 A008872 A008871

Adjacent sequences: A003939 A003940 A003941 this_sequence A003943 A003944 A003945

nonn,easy

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