A019918 Decimal expansion of tangent of 20 degrees.

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

Offset

0,1

Comments

Also the decimal expansion of cotangent of 70 degrees. - Mohammad K. Azarian, Jun 30 2013

Links

Ivan Panchenko, Table of n, a(n) for n = 0..1000

Index entries for algebraic numbers, degree 6.

Formula

Equals tan(Pi/9). - Bernard Schott, Apr 19 2022

Example

0.36397023426620236135104788277683404389047...

Maple

evalf(tan(Pi/9), 100); # Bernard Schott, Apr 19 2022

Mathematica

First[RealDigits[Tan[Pi/9], 10, 100]] (* Paolo Xausa, Aug 01 2024 *)

Prog

(PARI) tan(Pi/9) \\ Charles R Greathouse IV, Feb 05 2025
(PARI) polrootsreal(x^6-33*x^4+27*x^2-3)[4] \\ Charles R Greathouse IV, Feb 05 2025

Crossrefs

Cf. A019938 (tan(2*Pi/9)).

Sequence in context: A264767 A065231 A351102 * A260303 A055373 A263333

Adjacent sequences: A019915 A019916 A019917 * A019919 A019920 A019921

Keyword

nonn,cons

Author

N. J. A. Sloane

Status

approved