2,1

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.

Different from A003809.

Sequence in context: A059044 A107617 A003809 this_sequence A033425 A153751 A027664

Adjacent sequences: A003799 A003800 A003801 this_sequence A003803 A003804 A003805

nonn,easy

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