A373023 Decimal expansion of Sum_{k>=0} sin(3k*Pi/5)/2^k.

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

Offset

0,1

Links

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

Formula

Equals sqrt((5 + sqrt(5)]/(8 + 2 sqrt(5)).

Equals (-1)*Sum_{k>=0} sin(7 k*Pi/5)/2^k.

Minimal polynomial: 5 - 65 x^2 + 121 x^4.

Example

0.30501800805463899236580110742909107145...

Mathematica

{b, m, h} = {2, 5, 3}; s = Sum[Sin[ h k Pi/m]/b^k, {k, 0, Infinity}]
d = N[s, 100]
First[RealDigits[d], 100]

Crossrefs

Cf. A373021 (includes guide to related sequences).

Sequence in context: A276833 A166586 A122274 * A340525 A003966 A123931

Adjacent sequences: A373020 A373021 A373022 * A373024 A373025 A373026

Keyword

nonn,cons

Author

Clark Kimberling, Jul 20 2024

Status

approved