A380702 Decimal expansion of the acute vertex angles, in radians, in a (small) triakis octahedron face.

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

Offset: 0

Author

Paolo Xausa, Jan 30 2025

Keywords

• nonn
• cons
• easy

Examples

			0.54802840762031274453086328282062867847971236365920...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 0..10000
• Wikipedia, Triakis octahedron.

Crossrefs

Cf. A380703 (face obtuse angle).

Cf. A020765, A361601, A378351, A378352, A378353, A378354.

Programs

Mathematica

First[RealDigits[ArcCos[1/2 + Sqrt[2]/4], 10, 100]]

Formula

Equals arccos(1/2 + sqrt(2)/4) = arccos(1/2 + A020765).

Equals (Pi - A380703)/2.

Equals A361601/2. - Hugo Pfoertner, Jan 30 2025