A019849 Decimal expansion of sine of 40 degrees.

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

Offset

0,1

Comments

This sequence is also the decimal expansion of cosine of 50 degrees. - Mohammad K. Azarian, Jun 29 2013

A sextic number with denominator 2. - Charles R Greathouse IV, Nov 05 2017

Links

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

Formula

Equals cos(5*Pi/18) = 2F1(11/12,1/12;1/2;3/4) / 2. - R. J. Mathar, Oct 27 2008

Equals 2*A019829*A019879. - R. J. Mathar, Jan 17 2021

Example

0.642787609...

Mathematica

RealDigits[ Sin[ 2Pi/9], 10, 111][[1]] (* Robert G. Wilson v, Feb 16 2011 *)
RealDigits[Sin[40 Degree], 10, 120][[1]] (* Harvey P. Dale, Mar 27 2015 *)

Prog

(PARI) sin(2/9*Pi) \\ Charles R Greathouse IV, Nov 05 2017

Crossrefs

Sequence in context: A173625 A086036 A345644 * A244685 A118421 A158233

Adjacent sequences: A019846 A019847 A019848 * A019850 A019851 A019852

Keyword

nonn,cons

Author

N. J. A. Sloane

Status

approved