A019978 Decimal expansion of tangent of 80 degrees.

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

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• cons
• changed

Examples

			tan(4*Pi/9) = 5.67128183...
		

Links

• Ivan Panchenko, Table of n, a(n) for n = 1..1000
• Index entries for algebraic numbers, degree 6

Programs

Mathematica

RealDigits[Tan[80 Degree],10,120][[1]] (* Harvey P. Dale, Jan 04 2013 *)

Formula

Largest positive of the 6 real-valued roots of x^6-33*x^4+27*x^2-3=0. - R. J. Mathar, Aug 31 2025

Equals A019889/A019819. - R. J. Mathar, Aug 31 2025