A390638 Decimal expansion of the largest dihedral angle, in radians, in a sphenomegacorona (Johnson solid J_88).

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

Offset

1,1

Links

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

Polytope Wiki, Sphenomegacorona.

Wikipedia, Sphenomegacorona.

Formula

Equals arccos(c), where c = -0.9893886... is the smallest real root of 59049*x^16 - 314928*x^15 + 419904*x^14 + 542376*x^13 - 1641708*x^12 + 307152*x^11 + 1862352*x^10 - 1075032*x^9 - 609066*x^8 + 348720*x^7 - 71392*x^6 + 347416*x^5 - 64364*x^4 - 173520*x^3 + 52560*x^2 + 15000*x - 4375.

Example

2.9957832400120692992908056805273328034456543783317...

Mathematica

First[RealDigits[ArcCos[Root[59049*#^16 - 314928*#^15 + 419904*#^14 + 542376*#^13 - 1641708*#^12 + 307152*#^11 + 1862352*#^10 - 1075032*#^9 - 609066*#^8 + 348720*#^7 - 71392*#^6 + 347416*#^5 - 64364*#^4 - 173520*#^3 + 52560*#^2 + 15000*# - 4375 &, 1]], 10, 100]] (* or *)
First[RealDigits[Max[PolyhedronData["J88", "DihedralAngles"]], 10, 100]]

Crossrefs

Cf. other J_88 dihedral angles: A390630, A390631, A390632, A390633, A390634, A390635, A390636, A390637.

Cf. A334114 (J_88 volume), A010502 (J_88 surface area - 2).

Sequence in context: A021889 A309927 A016643 * A305308 A087042 A266274

Adjacent sequences: A390635 A390636 A390637 * A390639 A390640 A390641

Keyword

nonn,cons,easy

Author

Paolo Xausa, Nov 22 2025

Status

approved