A133749 Decimal expansion of -2*cos((2*Pi)/9) + 2*sqrt(3)*sin((2*Pi)/9).

6, 9, 4, 5, 9, 2, 7, 1, 0, 6, 6, 7, 7, 2, 1, 3, 9, 5, 4, 0, 6, 8, 6, 6, 5, 0, 7, 0, 7, 7, 2, 5, 9, 1, 8, 4, 0, 0, 1, 5, 0, 2, 7, 0, 8, 7, 3, 6, 2, 7, 7, 5, 4, 8, 9, 4, 4, 9, 6, 5, 5, 1, 2, 5, 2, 8, 2, 6, 3, 2, 8, 8, 5, 5, 6, 0, 5, 8, 9, 4, 1, 6, 8, 6, 0, 6, 6, 4, 5, 2, 6, 2, 9, 5, 9, 8, 2, 9, 6, 0, 4, 7, 8, 3, 6

Offset

0,1

Comments

The distance between the centers of 2 unit-radius spheres such that the volume of the overlap is equal to half the volume of each sphere. - Amiram Eldar, May 31 2021

Links

Table of n, a(n) for n=0..104.

Eric Weisstein's World of Mathematics, Sphere-Sphere Intersection.

Formula

Equals 4*sin(Pi/18) = 4*A019819. - Gleb Koloskov, Feb 28 2021

Example

0.69459271066772139540...

Mathematica

RealDigits[-2*Cos[(2*Pi)/9] + 2*Sqrt[3]*Sin[(2*Pi)/9], 10, 100][[1]] (* Vaclav Kotesovec, Aug 16 2015 *)

Prog

(PARI) 4*sin(Pi/18) \\ Gleb Koloskov, Feb 28 2021

Crossrefs

Cf. A019819.

Sequence in context: A216117 A021148 A269981 * A201130 A248759 A073240

Adjacent sequences: A133746 A133747 A133748 * A133750 A133751 A133752

Keyword

nonn,cons

Author

Eric W. Weisstein, Sep 23 2007

Status

approved