0,3

Or, number of inequivalent Delaunay [Delone] decompositions of R^n.

P. Engel, The contraction types of parallelohedra in E^5, Acta Cryst. A 56 (2002), 491-496.

M. I. Stogrin, Regular Dirichlet-Voronoi partitions for the second triclinic group, Trudy Matematicheskogo Instituta imeni V. A. Steklova, 123 (1973) = Proceedings of the Steklov Institute of Mathematics, 123 (1973).

Cf. A071880, A071881.

Sequence in context: A005114 A081090 A071880 this_sequence A081482 A134475 A114029

Adjacent sequences: A071879 A071880 A071881 this_sequence A071883 A071884 A071885

nonn,hard,nice

N. J. A. Sloane (njas(AT)research.att.com), Jun 10 2002