A058975 Total number of flats in the lattice of contractions of the n-cube. Also number of partitions of vertex set of n-cube into blocks all of which induce connected subgraphs.

1, 2, 12, 958, 27206608

Offset

0,2

References

J. N. Cooper, unpublished.

Links

Table of n, a(n) for n=0..4.

Frank Simon, Algebraic Methods for Computing the Reliability of Networks, Dissertation, Doctor Rerum Naturalium (Dr. rer. nat.), Fakultät Mathematik und Naturwissenschaften der Technischen Universität Dresden, 2012. - From N. J. A. Sloane, Jan 04 2013

Example

There are twelve contractions of the 2-cube, also known as the 4-cycle. The edge sets along which the contractions occur are: no edges, any one of the four single edges, one of two opposite pairs, one of four pairs of intersecting edges and all edges.

Crossrefs

Sequence in context: A129933 A064320 A112373 * A057120 A345976 A112512

Adjacent sequences: A058972 A058973 A058974 * A058976 A058977 A058978

Keyword

hard,nonn,nice

Author

Joshua N. Cooper (jcooper(AT)math.ucsd.edu), Jan 15 2001

Status

approved