A391148 Decimal expansion of the fourth largest dihedral angle, in radians, in a disphenocingulum (Johnson solid J_90).

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

Offset

1,1

Links

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

Polytope Wiki, Disphenocingulum.

Wikipedia, Disphenocingulum.

Formula

Equals arccos(c), where c = -0.7234004... is the seventh smallest real root of 119574225*x^24 - 2406364848*x^22 + 17789337936*x^20 - 70928084160*x^18 + 176524912224*x^16 - 294170745600*x^14 + 339776052480*x^12 - 275431891968*x^10 + 155839852800*x^8 - 59995938816*x^6 + 14865629184*x^4 - 2109210624*x^2 + 126877696.

Example

2.3795111183308585318170171374751830684709199646541...

Mathematica

First[RealDigits[ArcCos[Root[119574225*#^24 - 2406364848*#^22 + 17789337936*#^20 - 70928084160*#^18 + 176524912224*#^16 - 294170745600*#^14 + 339776052480*#^12 - 275431891968*#^10 + 155839852800*#^8 - 59995938816*#^6 + 14865629184*#^4 - 2109210624*#^2 + 126877696 &, 7]], 10, 100]] (* or *)
First[RealDigits[RankedMax[Union[PolyhedronData["J90", "DihedralAngles"]], 4], 10, 100]]

Crossrefs

Cf. other J_90 dihedral angles: A391145, A391146, A391147, A391149, A391150, A391151.

Cf. A386752 (J_90 volume), A385257 (J_90 surface area + 2).

Sequence in context: A053960 A114056 A378827 * A168222 A323384 A349641

Adjacent sequences: A391145 A391146 A391147 * A391149 A391150 A391151

Keyword

nonn,cons,easy

Author

Paolo Xausa, Dec 09 2025

Status

approved