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A004028 Geometric n-dimensional crystal classes.
(Formerly M1965)
3
1, 2, 10, 32, 227, 955, 7103 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

H. Brown, R. B\"{u}low, J. Neub\"{u}ser, H. Wondratschek and H. Zassenhaus, Crystallographic Groups of Four-Dimensional Space. Wiley, NY, 1978, p. 52.

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.

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

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.

W. Plesken and T. Schulz, CARAT Homepage

Experimental Mathematics, Home Page

CROSSREFS

Cf. A004027, A004029.

Sequence in context: A083099 A032095 A151019 * A236921 A080668 A062453

Adjacent sequences:  A004025 A004026 A004027 * A004029 A004030 A004031

KEYWORD

nonn,hard,nice

AUTHOR

N. J. A. Sloane.

EXTENSIONS

a(6) corrected from CARAT page by D. S. McNeil, Jan 02 2011

STATUS

approved

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Last modified November 27 04:47 EST 2014. Contains 250155 sequences.