OFFSET
0,3
COMMENTS
Polytetrahedra are a 3-dimensional generalization of polyiamonds, composed of unit regular tetrahedra in Euclidean 3-space. - Peter Kagey, Aug 05 2019, adapted from comment by Jonathan Vos Post.
LINKS
Andrew I. Campbell, Valerie J. Anderson, Jeroen S. van Duijneveldt and Paul Bartlett, Dynamical Arrest in Attractive Colloids: The Effect of Long-Range Repulsion, Phys. Rev. Lett. 94, 208301 (2005).
Peter Kagey, Examples of the seven shapes that can be constructed from three tetrahedra, with Mathematica code.
J. F. Sadoc, Boerdijk-Coxeter helix and biological helices, Eur. Phys. J. B 12, 309-318.
Jonathan Vos Post, Original example for entry.
Eric Weisstein et al., Tetrahedron.
Wikipedia, Polyiamond
Wikipedia, Deltahedron
EXAMPLE
For n = 1, the a(1) = 1 polytetrahedron is the tetrahedron itself.
For n = 2, the a(2) = 2 polytetrahedra are formed by either gluing two tetrahedra along a face (triangular bipyramid) or gluing two tetrahedra along an edge.
For n = 7, the a(3) = 7 polytetrahedra are given in the links section.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Jonathan Vos Post, Jun 02 2006
STATUS
approved