OFFSET
0,4
REFERENCES
H. S. M. Coxeter, Regular Polytopes, 3rd ed., Dover, NY, 1973.
B. Grünbaum, Convex Polytopes. Wiley, NY, 1967, p. 424.
P. McMullen and E. Schulte, Abstract Regular Polytopes, Encyclopedia of Mathematics and its Applications, Vol. 92, Cambridge University Press, Cambridge, 2002.
LINKS
John Baez, Platonic Solids in All Dimensions, Nov 12 2006
Brady Haran, Pete McPartlan, and Carlo Sequin, Perfect Shapes in Higher Dimensions, Numberphile video (2016)
Index entries for linear recurrences with constant coefficients, signature (1).
FORMULA
a(n) = 3 for all n > 4. - Christian Schroeder, Nov 16 2015
EXAMPLE
a(2) = -1 because of the regular polygons in the plane.
a(3) = 5 because in R^3 the regular convex polytopes are the 5 Platonic solids.
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Ahmed Fares (ahmedfares(AT)my-deja.com), Mar 24 2001
STATUS
approved