A390284 Decimal expansion of the fourth smallest dihedral angle, in radians, in a sphenocorona (Johnson solid J_86).

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

Offset

1,1

Comments

Also a dihedral angle in an augmented sphenocorona (Johnson solid J_87).

Links

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

Polytope Wiki, Sphenocorona.

Wikipedia, Sphenocorona.

Index entries for transcendental numbers

Formula

Equals arccos(c), where c = (1 - sqrt(6))/3 = -0.483163... is the negative root of 9*x^2 - 6*x - 5.

Example

2.07506040293586876663264592163747761508712360972...

Mathematica

First[RealDigits[ArcCos[(1 - Sqrt[6])/3], 10, 100]] (* or *)
First[RealDigits[RankedMin[Union[PolyhedronData["J86", "DihedralAngles"]], 4], 10, 100]]

Crossrefs

Cf. other J_86 dihedral angles: A390281, A390282, A390283, A390285, A390286, A390287, A390288.

Cf. A386739 (J_86 volume), A010482 (J_86 surface area - 2).

Sequence in context: A326731 A021486 A258990 * A388147 A351727 A337450

Adjacent sequences: A390281 A390282 A390283 * A390285 A390286 A390287

Keyword

nonn,cons,easy

Author

Paolo Xausa, Nov 03 2025

Status

approved