A019964 Decimal expansion of tangent of 66 degrees.

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

Offset

1,1

Comments

Also the decimal expansion of cotangent of 24 degrees. - Ivan Panchenko, Sep 01 2014

A root of 1-92*x^2+134*x^4-28*x^6+x^8=0. - R. J. Mathar, Sep 06 2025

Links

Ivan Panchenko, Table of n, a(n) for n = 1..1000

Wikipedia, Exact trigonometric constants.

Index entries for algebraic numbers, degree 8.

Formula

Equals tan(11*Pi/30).

Equals A019857/(1-A019851) = A019875/A019833. - R. J. Mathar, Sep 06 2025

Equals 1/A019922. - Amiram Eldar, Jun 12 2026

Example

2.24603677390421605416332143841640915914036310102689708141...

Mathematica

RealDigits[Tan[66*Pi/180], 10, 100][[1]] (* G. C. Greubel, Nov 21 2018 *)

Prog

(PARI) default(realprecision, 100); tan(11*Pi/30) \\ G. C. Greubel, Nov 21 2018
(Magma) SetDefaultRealField(RealField(100)); R:= RealField(); Tan(11*Pi(R)/30); // G. C. Greubel, Nov 21 2018
(SageMath) numerical_approx(tan(11*pi/30), digits=100) # G. C. Greubel, Nov 21 2018

Crossrefs

Cf. A019833, A019851, A019857, A019875 (sine 66 degrees), A019922.

Sequence in context: A389805 A158649 A357886 * A087377 A010768 A373208

Adjacent sequences: A019961 A019962 A019963 * A019965 A019966 A019967

Keyword

nonn,cons,changed

Author

N. J. A. Sloane

Status

approved