A085550 Decimal expansion of (sqrt(13)-3)/2.

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

Offset: 0

Author

Cino Hilliard, Jul 04 2003

Keywords

• easy
• cons
• nonn

Examples

			0.30277563773199464655961...
		

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 0..10000
• Cino Hilliard, + N = Reciprocal Recursion [broken link]
• Index entries for algebraic numbers, degree 2.

Crossrefs

Cf. A010470 (sqrt(13)).

Programs

Mathematica

First[RealDigits[(Sqrt[13] - 3)/2, 10, 100]] (* Paolo Xausa, Jun 12 2024 *)

PARI

(sqrt(13)-3)/2 \\ Michel Marcus, Jan 16 2020

Formula

Equals Sum_{k>=1} (-1)^(k-1)/(A006190(k)*A006190(k+1)). - Vladimir Shevelev, Feb 23 2013

Tan(arctan(c) + arctan(c^3)) = 1/3. - Gary W. Adamson, Apr 02 2024