OFFSET
3,1
COMMENTS
a(0), a(1) and a(2) are all infinite, because their symmetry groups are continuous (they contain rotations with arbitrary angles). Actual symmetry groups: 3 D_{3h}, 4 T_{d}, 5 D_{3h}, 6 O_{d}, 7 D_{5h}, 8 D_{4d}, 9 D_{3h}, 10 D_{4h}, 11 D_{1h}, 12 I_{d}, 13 D_{1h}.
LINKS
K. S. Brown, Min-Energy Configurations of Electrons On A Sphere, MathPages.
R. H. Hardin, N. J. A. Sloane and W. D. Smith, Minimal Energy Configurations of Points on a Sphere
Wikipedia, Thomson Problem.
EXAMPLE
a(3)=12 because the minimal-energy configuration of 3 charged particles on a sphere is an equilateral triangle on the equator, which has symmetry group D_3h of order 12.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Keenan Pepper, Nov 30 2007
STATUS
approved