A390145 Decimal expansion of the largest dihedral angle, in radians, in a snub disphenoid (Johnson solid J_84).

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

Offset

1,1

Links

Paolo Xausa, Table of n, a(n) for n = 1..10000

Polytope Wiki, Snub disphenoid.

Wikipedia, Snub disphenoid.

Formula

Equals arccos(c), where c is the smallest root of 27*x^3 - 45*x^2 - 24*x + 44.

Example

2.904935646441255214401380074990057843793815602886...

Mathematica

First[RealDigits[ArcCos[Root[27*#^3 - 45*#^2 - 24*# + 44 &, 1]], 10, 100]] (* or *)
First[RealDigits[Max[PolyhedronData["J84", "DihedralAngles"]], 10, 100]]

Crossrefs

Cf. other J_84 dihedral angles: A390143, A390144.

Cf. A386695 (J_84 volume), A010482 (J_84 surface area).

Sequence in context: A019969 A185362 A140239 * A221200 A221245 A340009

Adjacent sequences: A390142 A390143 A390144 * A390146 A390147 A390148

Keyword

nonn,cons,easy

Author

Paolo Xausa, Oct 28 2025

Status

approved