A390981 Decimal expansion of the second largest dihedral angle, in radians, in a hebesphenomegacorona (Johnson solid J_89).

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

Offset

1,1

Links

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

Polytope Wiki, Hebesphenomegacorona.

Wikipedia, Hebesphenomegacorona.

Formula

Equals arccos(c), where c = -0.8908129... is the fourth smallest real root of 3869835264*x^20 - 33538572288*x^18 + 146946244608*x^16 - 394705281024*x^14 + 693728810496*x^12 - 791487687168*x^10 + 544315308480*x^8 - 186535326816*x^6 + 10976741577*x^4 + 5975898216*x^2 + 454030864.

Example

2.6699275191275852075533310850818946957363061920773...

Mathematica

First[RealDigits[ArcCos[Root[3869835264*#^20 - 33538572288*#^18 + 146946244608*#^16 - 394705281024*#^14 + 693728810496*#^12 - 791487687168*#^10 + 544315308480*#^8 - 186535326816*#^6 + 10976741577*#^4 + 5975898216*#^2 + 454030864 &, 4]], 10, 100]] (* or *)
First[RealDigits[RankedMax[Union[PolyhedronData["J89", "DihedralAngles"]], 2], 10, 100]]

Crossrefs

Cf. other J_89 dihedral angles: A390975, A390976, A390977, A390978, A390979, A390980, A390982.

Cf. A386741 (J_89 volume), A386742 (J_89 surface area).

Sequence in context: A377998 A372610 A021978 * A141377 A006955 A306745

Adjacent sequences: A390978 A390979 A390980 * A390982 A390983 A390984

Keyword

nonn,cons,easy

Author

Paolo Xausa, Dec 01 2025

Status

approved