A387296 Decimal expansion of the third largest dihedral angle, in radians, in a gyroelongated triangular cupola (Johnson solid J_22).

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

Offset: 1

Author

Paolo Xausa, Aug 26 2025

Keywords

• nonn
• cons
• easy
• new

Comments

This is the dihedral angle between triangular faces in the antiprism part of the solid.

Also the analogous dihedral angle in a gyroelongated triangular bicupola (Johnson solid J_44).

Examples

			2.5346001497151261930915028102102107021498303291935...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000
• Wikipedia, Gyroelongated triangular bicupola.
• Wikipedia, Gyroelongated triangular cupola.

Crossrefs

Cf. other J_22 dihedral angles: A195698, A387294, A387295, A387297.

Cf. A344076 (J_22 volume), A344077 (J_22 surface area).

Cf. A385256 (J_44 volume), A385257 (J_44 surface area).

Cf. A010469.

Programs

Mathematica

First[RealDigits[ArcCos[(1 - Sqrt[12])/3], 10, 100]] (* or *)
First[RealDigits[RankedMax[Union[PolyhedronData["J22", "DihedralAngles"]], 3], 10, 100]]

Formula

Equals arccos((1 - 2*sqrt(3))/3) = arccos((1 - A010469)/3).