A390285 Decimal expansion of the fourth largest dihedral angle, in radians, in a sphenocorona (Johnson solid J_86).

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

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 = (164*sqrt(6) - 8*sqrt(2743 - 977*sqrt(6)) - 401)/225 = -0.6618559... is the largest negative root of 18225*x^4 + 129924*x^3 + 104742*x^2 - 58236*x - 50255.

Example

2.29408819556486390122704964609168217987688892368...

Mathematica

First[RealDigits[ArcCos[(164*Sqrt[6] - 8*Sqrt[2743 - 977*Sqrt[6]] - 401)/225], 10, 100]] (* or *)
First[RealDigits[RankedMax[Union[PolyhedronData["J86", "DihedralAngles"]], 4], 10, 100]]

Crossrefs

Cf. other J_86 dihedral angles: A390281, A390282, A390283, A390284, A390286, A390287, A390288.

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

Sequence in context: A271524 A157216 A388365 * A020776 A384278 A021002

Adjacent sequences: A390282 A390283 A390284 * A390286 A390287 A390288

Keyword

nonn,cons,easy

Author

Paolo Xausa, Nov 03 2025

Status

approved