A019836 Decimal expansion of sine of 27 degrees.

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

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• cons
• changed

Comments

An algebraic number of degree 8 and denominator 2. - Charles R Greathouse IV, Aug 27 2017

Links

• Ivan Panchenko, Table of n, a(n) for n = 0..1000
• Wikipedia, Trigonometric constants expressed in real radicals
• Index entries for algebraic numbers, degree 8

Programs

Mathematica

RealDigits[Sin[27 Degree],10,120][[1]] (* Harvey P. Dale, Nov 09 2014 *)

PARI

cos(7*Pi/20) \\ Charles R Greathouse IV, Aug 27 2017

Formula

Equals A019827 * A019890 + A019818 * A019881 = A019833 * A019896 + A019812 * A019875. - R. J. Mathar, Jan 27 2021

Equals cos(7*Pi/20). 2*this^2-1 = -A019845. - R. J. Mathar, Aug 29 2025