OFFSET
1,1
COMMENTS
Equals 5*phi^3/(2*xi^2), phi being the golden ratio (A001622) and xi its associate (A182007). - Stanislav Sykora, Nov 23 2013
LINKS
Ivan Panchenko, Table of n, a(n) for n = 1..1000
Eric Weisstein's World of Mathematics, Dodecahedron
Wikipedia, Platonic solid
FORMULA
Equals (15 + 7 sqrt(5)) / 4.
Equals (sqrt(5)/2)*(phi)^4, where phi is the golden ratio. - G. C. Greubel, Jul 06 2017
EXAMPLE
7.663118960624631968716053920...
MAPLE
evalf((15+7*sqrt(5))/4, 100); # Wesley Ivan Hurt, Jan 29 2017
MATHEMATICA
RealDigits[(Sqrt[5]/2)*(GoldenRatio)^4, 10, 50][[1]] (* G. C. Greubel, Jul 06 2017 *)
PROG
(PARI) (7*sqrt(5)+15)/4 \\ Charles R Greathouse IV, Apr 25 2016
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Bryan Jacobs (bryanjj(AT)gmail.com), Feb 10 2005
STATUS
approved