A373018 Decimal expansion of Sum_{k>=0} |sin(k*Pi/3)|/2^k.

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

Offset

0,1

Links

Table of n, a(n) for n=0..85.

Index entries for algebraic numbers, degree 2.

Formula

Equals (3/7)*sqrt(3).

Example

0.7423074889580902686546198606453738715469165373...

Mathematica

s = Sum[Abs[Sin[k Pi/3]]/2^k, {k, 0, Infinity}]
d = N[s, 100]
First[RealDigits[d]]

Prog

(PARI) sqrt(27)/7 \\ Charles R Greathouse IV, Jun 08 2026

Crossrefs

Cf. A373021.

Sequence in context: A021578 A273093 A071185 * A165244 A198356 A377753

Adjacent sequences: A373015 A373016 A373017 * A373019 A373020 A373021

Keyword

nonn,cons

Author

Clark Kimberling, Jul 16 2024

Status

approved