OFFSET
1,2
COMMENTS
Also the vertex solid angle of a regular octahedron.
LINKS
Stanislav Sykora, Table of n, a(n) for n = 1..2000
Eric Weisstein's World of Mathematics, Cuboctahedron.
Eric Weisstein's World of Mathematics, Spherical Polygon.
Wikipedia, Platonic solid.
FORMULA
Equals 4*arcsin(1/3) = 4*A188615.
Equals 2*Pi - 4*arcsin(2*sqrt(2)/3). - Bradley Klee, Oct 04 2018
8*A236555 + 6*this = 4*Pi. - Bradley Klee, Oct 04 2018
EXAMPLE
1.35934763781648774838557005356705626555297876132983228572769584995966...
MAPLE
evalf(4*arcsin(1/3), 100) ; # R. J. Mathar, Apr 26 2021
MATHEMATICA
RealDigits[4*ArcSin[1/3], 10, 120][[1]] (* Amiram Eldar, May 22 2023 *)
PROG
(PARI) 4*asin(1/3)
CROSSREFS
KEYWORD
AUTHOR
Stanislav Sykora, Jan 28 2014
EXTENSIONS
Definition corrected by Bradley Klee, Oct 04 2018
STATUS
approved