A195698 - OEIS

A195698

Decimal expansion of arccos(-sqrt(1/3)).

2, 1, 8, 6, 2, 7, 6, 0, 3, 5, 4, 6, 5, 2, 8, 3, 9, 6, 0, 2, 9, 8, 7, 8, 6, 2, 8, 0, 7, 6, 3, 7, 4, 5, 1, 2, 9, 9, 5, 3, 7, 5, 4, 7, 0, 4, 3, 6, 5, 1, 0, 0, 3, 3, 0, 0, 1, 5, 2, 4, 6, 4, 6, 2, 9, 8, 5, 9, 0, 4, 3, 6, 0, 3, 8, 2, 2, 3, 2, 5, 4, 3, 2, 4, 0, 6, 4, 3, 2, 2, 2, 7, 5, 6, 4, 8, 8, 9, 9, 4 (list; constant; graph; refs; listen; history; text; internal format)

	OFFSET	`1,1`
	COMMENTS	`Dihedral angle between mixed type faces of the truncated octahedron. - R. J. Mathar, Mar 24 2012`
	LINKS	`G. C. Greubel, Table of n, a(n) for n = 1..5000` `Wikipedia, Truncated Octahedron.`
	FORMULA	`Equals Pi - arcsin(sqrt(2/3)) = Pi - arctan(sqrt(2)). - Amiram Eldar, Jul 08 2023`
	EXAMPLE	`arccos(-1/sqrt(3)) = 2.1862760354...`
	MATHEMATICA	`(See A195695.)` `RealDigits[ArcCos[-1/Sqrt[3]], 10, 50][[1]] (* G. C. Greubel, Nov 18 2017 *)`
	PROG	`(PARI) acos(-1/sqrt(3)) \\ G. C. Greubel, Nov 18 2017` `(Magma) [Arccos(-1/Sqrt(3))]; // G. C. Greubel, Nov 18 2017`
	CROSSREFS	`Cf. A195695.` `Sequence in context: A108084 A305860 A272983 * A193908 A193904 A154897` `Adjacent sequences: A195695 A195696 A195697 * A195699 A195700 A195701`
	KEYWORD	`nonn,cons`
	AUTHOR	`Clark Kimberling, Sep 23 2011`
	STATUS	`approved`