A378354 Decimal expansion of the dihedral angle, in radians, between any two adjacent faces in a (small) triakis octahedron.

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

Offset: 1

Author

Paolo Xausa, Nov 24 2024

Keywords

• nonn
• cons
• easy

Comments

The (small) triakis octahedron is the dual polyhedron of the truncated cube.

Examples

			2.57174440034566846791285405092806379355115694111...
		

Links

• Wikipedia, Triakis octahedron.

Crossrefs

Cf. A378351 (surface area), A378352 (volume), A378353 (inradius), A201488 (midradius).

Cf. A019669 and A195698 (dihedral angles of a truncated cube).

Cf. A377342.

Programs

Mathematica

First[RealDigits[ArcCos[-(3 + 8*Sqrt[2])/17], 10, 100]] (* or *)
First[RealDigits[First[PolyhedronData["TriakisOctahedron", "DihedralAngles"]], 10, 100]]

Formula

Equals arccos(-(3 + 8*sqrt(2))/17) = arccos(-(3 + A377342)/17).