OFFSET
1,2
COMMENTS
Equivalently, the area in the complex plane of the smallest convex set containing all order-3 roots of unity.
LINKS
Eric Weisstein et al., Root of Unity.
Eric Weisstein's World of Mathematics, de Moivre Number.
I. J. Zucker and G. S. Joyce, Special values of the hypergeometric series II, Math. Proc. Camb. Phil. Soc. 131 (2001) 309-319.
FORMULA
Equals 3*sqrt(3)/4.
Equals (1/2)*A104956.
Equals 2F1(1/6,1/3 ; 1/2 ; 25/27). [Zucker] - R. J. Mathar, Jun 24 2024
EXAMPLE
1.299038105676657970145584756129404275207103940357785471...
MATHEMATICA
RealDigits[N[Floor[n/2]*Sin[(2*Pi)/n] - Sin[(4*Pi*Floor[n/2])/n]/2 /. n -> 3, 108]][[1]]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Joseph Biberstine (jrbibers(AT)indiana.edu), Mar 30 2005
EXTENSIONS
Edited by Georg Fischer, Jul 29 2021
STATUS
approved