OFFSET
1,1
COMMENTS
The sum of four easily recognized geometric series that have common ratio 9/64.
An algebraic number with minimal polynomial 1369x^2 - 6216x + 6468. - Charles R Greathouse IV, Oct 29 2016
LINKS
Michelle Huff, Table of n, a(n) for n = 1..10000
FORMULA
Equals (14/37)*(6 + sqrt(3)).
EXAMPLE
2.92564084610714275971308780...
MATHEMATICA
r = Sqrt[3]/2; u = Simplify[r (1 + r + r^3 - r^4)/(1 - r^6)]
RealDigits[N[u, 120], 10][[1]]
PROG
(PARI) suminf(n=1, sin((n*Pi)/3)^n) \\ Michel Marcus, Oct 29 2016
(PARI) (sqrt(3)+6)*14/37 \\ Charles R Greathouse IV, Oct 29 2016
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Michelle Huff, Oct 28 2016
STATUS
approved