A006226 Number of abstract n-dimensional crystallographic point groups. (Formerly M1916)

1, 2, 9, 18, 118, 239, 1594

Offset

0,2

References

P. Engel, "Geometric crystallography," in P. M. Gruber and J. M. Wills, editors, Handbook of Convex Geometry. North-Holland, Amsterdam, Vol. B, pp. 989-1041.

T. Janssen, Crystallographic Groups. North-Holland, Amsterdam, 1973, p. 73.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=0..6.

A. C. Hurley, Finite rotation groups and crystal classes in four dimensions, Proc. Cambridge Philos. Soc. 47, (1951). 650-661.

A. C. Hurley, Crystal Classes of Four-Dimensional Space R4, Acta Crystallog., 22 (1967), see especially p. 605.

W. Plesken and T. Schulz, Counting crystallographic groups in low dimensions, Experimental Mathematics, 9 (No. 3, 2000), 407-411.

W. Plesken and T. Schulz, CARAT Homepage

W. Plesken and T. Schulz, CARAT Homepage [Cached copy in pdf format (without subsidiary pages), with permission]

W. Plesken and T. Schulz, Introduction to CARAT [Cached copy in pdf format (without subsidiary pages), with permission]

E. S. Rosenthal & N. J. A. Sloane, Correspondence, 1975

Crossrefs

Cf. A004027, A004028, A004029.

Sequence in context: A037421 A083423 A068978 * A109298 A297470 A075537

Adjacent sequences: A006223 A006224 A006225 * A006227 A006228 A006229

Keyword

hard,nonn,more,nice

Author

N. J. A. Sloane

Extensions

Two more terms from W. Plesken and T. Schulz (tilman(AT)momo.math.rwth-aachen.de), Feb 27 2001

Offset corrected by Andrey Zabolotskiy, Jul 10 2017

Status

approved