OFFSET
0,1
COMMENTS
Icosahedron: A three-dimensional figure with 20 equilateral triangle faces, 12 vertices, and 30 edges.
LINKS
Ivan Panchenko, Table of n, a(n) for n = 0..1000
Dr. Math, Icosahedron
Wikipedia, Icosahedron
MathWorld, Icosahedron
FORMULA
Sqrt(42 + 18*sqrt(5))/12.
EXAMPLE
0.75576131407617073048013370202500139263844478889356105922958289203910...
MATHEMATICA
a=1; RealDigits[N[(Sqrt[42+18Sqrt[5]]/12)*a, 175]]
CROSSREFS
KEYWORD
AUTHOR
Vladimir Joseph Stephan Orlovsky, Jul 09 2010
EXTENSIONS
Partially rewritten by Charles R Greathouse IV, Feb 03 2011
STATUS
approved