A390281 Decimal expansion of the smallest dihedral angle, in radians, in a sphenocorona (Johnson solid J_86).

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

Offset

1,2

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 = -sqrt((5 - 2*sqrt(6))/6) = -0.1297565... is the largest negative root of 36*x^4 - 60*x^2 + 1.

Example

1.7009197385208883341876458658494163618110152503917...

Mathematica

First[RealDigits[ArcCos[-Sqrt[(5 - 2*Sqrt[6])/6]], 10, 100]] (* or *)
First[RealDigits[Min[PolyhedronData["J86", "DihedralAngles"]], 10, 100]]

Crossrefs

Cf. other J_86 dihedral angles: A390282, A390283, A390284, A390285, A390286, A390287, A390288.

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

Sequence in context: A154102 A388254 A344785 * A240984 A235363 A356592

Adjacent sequences: A390278 A390279 A390280 * A390282 A390283 A390284

Keyword

nonn,cons,easy

Author

Paolo Xausa, Nov 03 2025

Status

approved