A372777 Decimal expansion of (4 + 5*sqrt(2))/17.

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

Offset

0,1

Links

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

Index entries for algebraic numbers, degree 2.

Formula

Equals (4 + 5*sqrt(2))/17 = Sum_{k>=0} sin(k*Pi)/2^k.

Minimal polynomial: 17*x^2 - 8*x - 2. - Amiram Eldar, May 26 2026

Example

0.65123928305091030847108491888520531722637408099322002...

Mathematica

s = Sum[Sin[k Pi/4]/2^k, {k, 0, Infinity}]
d = N[s, 100]
First[RealDigits[d]]
N[(1/17) (4 + 5  Sqrt[2]), 100]

Prog

(PARI) (4+5*sqrt(2))/17 \\ Charles R Greathouse IV, Apr 30 2026

Crossrefs

Cf. A372778, A372830.

Sequence in context: A373019 A126743 A046613 * A296470 A195774 A320833

Adjacent sequences: A372774 A372775 A372776 * A372778 A372779 A372780

Keyword

nonn,cons

Author

Clark Kimberling, Jun 07 2024

Status

approved