A386435 Decimal expansion of the largest dihedral angle, in radians, in a triangular bipyramid (Johnson solid J_12).

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

Offset: 1

Author

Paolo Xausa, Aug 20 2025

Keywords

• nonn
• cons
• easy

Comments

Also the largest dihedral angle in a triangular orthobicupola (Johnson solid J_27) and the second largest dihedral angle in an augmented truncated tetrahedron (Johnson solid J_65).

Examples

			2.461918834681549364269858356495974751420680018710...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000
• Wikipedia, Augmented truncated tetrahedron.
• Wikipedia, Triangular bipyramid.
• Wikipedia, Triangular orthobicupola.

Crossrefs

Cf. A137914 (J_12 smallest dihedral angle).

Cf. A020775 (J_12 volume), A104956 (J_12 surface area).

Programs

Mathematica

First[RealDigits[ArcCos[-7/9], 10, 100]] (* or *)
First[RealDigits[Max[PolyhedronData["J12", "DihedralAngles"]], 10, 100]]

Formula

Equals arccos(-7/9).