A390288 Decimal expansion of the largest dihedral angle, in radians, in a sphenocorona (Johnson solid J_86).

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

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 = (144*sqrt(6) - 8*sqrt(538 + 18*sqrt(6)) - 371)/225 = -0.9390486... is the largest negative root of 18225*x^4 + 120204*x^3 + 182934*x^2 - 56724*x - 129215.

Example

2.7906487660799651007194189352846543881206213794840...

Mathematica

First[RealDigits[ArcCos[(144*Sqrt[6] - 8*Sqrt[538 +18*Sqrt[6]] - 371)/225], 10, 100]] (* or *)
First[RealDigits[Max[PolyhedronData["J86", "DihedralAngles"]], 10, 100]]

Crossrefs

Cf. other J_86 dihedral angles: A390281, A390282, A390283, A390284, A390285, A390286, A390287.

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

Sequence in context: A198322 A372422 A371331 * A389521 A222134 A011355

Adjacent sequences: A390285 A390286 A390287 * A390289 A390290 A390291

Keyword

nonn,cons,easy

Author

Paolo Xausa, Nov 03 2025

Status

approved