cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A335864 Decimal expansion of the negative of the zero x3 of the cubic polynomial x^3 - 2*x^2 - 10*x - 6.

Original entry on oeis.org

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

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Author

Wolfdieter Lang, Jun 29 2020

Keywords

Comments

For details and links see A335862.

Examples

			-x3 = 0.758886842296941304849382284375859546...
		

Crossrefs

Cf. A335862 (x1), A335863 (-x2).

Programs

  • Maple
    evalf((f-> (sqrt(34)*(cos(f)-sin(f)*sqrt(3))-2)/3)(arctan(sqrt(807)*3/179)/3), 120);  # Alois P. Heinz, Nov 17 2020
  • Mathematica
    With[{j = Sqrt[3] I, k = 3 Sqrt[3] Sqrt[269] I}, First@ RealDigits[Re[(1/3) (2 - (1/2) (1 + j) (179 + k)^(1/3) - (1/2) (1 - j) (179 - k)^(1/3))], 10, 97]] (* Michael De Vlieger, Nov 17 2020 *)

Formula

-x3 = (1/3)*(2 - (1/2)*(1 + sqrt(3)*i)*(179 + 3*sqrt(3)*sqrt(269)*i)^(1/3) - (1/2)*(1 - sqrt(3)*i)*(179 - 3*sqrt(3)*sqrt(269)*i)^(1/3)), where i is the imaginary unit.