

A092240


a(n) is the number of ndimensional symmetry frieze designs (incorrect).


0




OFFSET

1,1


COMMENTS

I suspect that some of the contributors to this entry have confused it with A004029. The term 4783 is probably wrong, since A004029(4) = 4783.  N. J. A. Sloane, Dec 27 2014
As far as I can tell, the values given in this sequence are not consistent with any possible interpretation of "Frieze". The standard Frieze groups are defined as the 2D line groups (planar symmetry groups having a translation in one direction only). In one dimension, there are only 2 line groups (not 7), and 0 if we discount the groups having a translation in one direction (both of them). In three dimensions, there are the 219 or 230 crystallographic groups (depending on whether chiral copies are considered distinct), but these have translations in 3 directions. If we count groups having fewer than 3 translations, then there are just 80 layer groups (having translations in two directions), and 75 rod groups (having translations in one direction).  Brian Galebach, Oct 18 2016


REFERENCES

Piergiorgio Odifreddi, The Mathematical Century: The 30 Greatest Problems of the Last 100 Years, Princeton University Press, 2004, see p. 102.


LINKS

Table of n, a(n) for n=1..4.
Yanxi Liu, Collins, R.T., Tsin, Y., A computational model for periodic pattern perception based on frieze and wallpaper groups, IEEE Trans. Pattern Analysis and Machine Intelligence, 26 (2004), 354371.


EXAMPLE

There are 7 strip patterns, i.e., 1dimensional symmetry frieze designs; 17 wallpaper designs, i.e., 2dimensional symmetry groups; 230 is the number of crystallographic groups, i.e., 3dimensional symmetry designs; 4783 is the 4dimensional extension of the above.


CROSSREFS

Cf. A004029, A006227.
Sequence in context: A061159 A178694 A140122 * A110120 A201305 A053584
Adjacent sequences: A092237 A092238 A092239 * A092241 A092242 A092243


KEYWORD

dead


AUTHOR

Nitsa MovshovitzHadar (nitsa(AT)tx.technion.ac.il), Oct 24 2004


STATUS

approved



