Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
H. Brown, R. Bülow, J. Neubüser, H. Wondratschek and H. Zassenhaus, Crystallographic Groups of Four-Dimensional Space. Wiley, NY, 1978, p. 52.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Table of n, a(n) for n=0..6.
W. Plesken and T. Schulz, Counting crystallographic groups in low dimensions, Experimental Mathematics, Volume 9 Issue 3 (2000), 321-478
Cf. A004027-A004031, A006226, A006227.
Sequence in context: A061597 A075813 A107952 * A123046 A237748 A087784
Adjacent sequences: A004029 A004030 A004031 * A004033 A004034 A004035
N. J. A. Sloane.
a(5)-a(6) from Henry Bottomley, Feb 03 2014