A019830 Decimal expansion of sine of 21 degrees.

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

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• cons

Links

• Ivan Panchenko, Table of n, a(n) for n = 0..1000
• Wikipedia, Trigonometric constants expressed in real radicals

Crossrefs

Cf. A019812, A019816, A019823, A019827, A019881, A019892, A019885, A019896.

Programs

Mathematica

RealDigits[Sin[21 Degree],10,120][[1]] (* Harvey P. Dale, Apr 06 2016 *)

PARI

sin(7*Pi/60) \\ Charles R Greathouse IV, Jan 30 2016

Formula

Equals A019823*A019892 + A019816*A019885 = A019827*A019896 + A019812*A019881. - R. J. Mathar, Jan 27 2021