A390286 Decimal expansion of the third largest dihedral angle, in radians, in a sphenocorona (Johnson solid J_86).

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

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 = (2*sqrt(6) - 4*sqrt(213 - 57*sqrt(6)) - 3)/45 = -0.7192368... is the largest negative root of 135*x^4 + 36*x^3 - 454*x^2 + 4*x + 215.

Example

2.37349957044744889051658499629743649038822792668...

Mathematica

First[RealDigits[ArcCos[(Sqrt[24] - 4*Sqrt[213 - 57*Sqrt[6]] - 3)/45], 10, 100]] (* or *)
First[RealDigits[RankedMax[Union[PolyhedronData["J86", "DihedralAngles"]], 3], 10, 100]]

Crossrefs

Cf. other J_86 dihedral angles: A390281, A390282, A390283, A390284, A390285, A390287, A390288.

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

Sequence in context: A336052 A174606 A096389 * A054144 A226985 A174407

Adjacent sequences: A390283 A390284 A390285 * A390287 A390288 A390289

Keyword

nonn,cons,easy

Author

Paolo Xausa, Nov 03 2025

Status

approved