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A119602
Number of nonisomorphic polytetrahedra with n identical regular tetrahedra connected face-to-face or edge-to-edge (chiral shapes counted twice).
2
1, 1, 2, 7, 39
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).
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
Sequence in context: A222034 A337685 A014058 * A121752 A054133 A330470
KEYWORD
nonn,more
AUTHOR
Jonathan Vos Post, Jun 02 2006
STATUS
approved