1,2

J. H. Conway and N. J. A. Sloane, "Low-Dimensional Lattices II: Subgroups of GL(n,Z)", Proc. Royal Soc. London, A 419 (1988), 29-68.

Peter Engel, Geometric Crystallography, D. Reidel, Dordrecht, Holland, 1968. ISBN 90-277-2339-7. See Table 6.3, p. 111.

Sequence in context: A034901 A109976 A011768 this_sequence A067951 A131862 A131857

Adjacent sequences: A052484 A052485 A052486 this_sequence A052488 A052489 A052490

nonn,nice

Frederick G. Schmitt (fred(AT)marin.cc.ca.us), Mar 16 2000