A373025 Decimal expansion of Sum_{k>=0} cos(k*Pi/5)/2^k.

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

Offset: 1

Author

Clark Kimberling, Jul 20 2024

Keywords

• nonn
• cons

Examples

			1.3503729060226985949648873184633558...
		

Crossrefs

Cf. A373021 (includes guide to related sequences).

Programs

Mathematica

{b, m, h} = {2, 5, 1}; s = Sum[Cos[ h  k  Pi/m]/b^k, {k, 0, Infinity}]
d = N[s, 100]
First[RealDigits[d], 100]

Formula

Equals (23 + 3*sqrt(5))/22.

Equals Sum_{k>=0} cos(9 k*Pi/5)/2^k.

Minimal polynomial: 11 - 23 x + 11 x^2.