A378977 Decimal expansion of the dihedral angle, in radians, between any two adjacent faces in a triakis icosahedron.
2, 8, 0, 3, 2, 1, 7, 8, 5, 6, 0, 8, 4, 8, 0, 5, 9, 6, 2, 1, 0, 3, 4, 4, 9, 3, 2, 6, 4, 8, 7, 7, 2, 5, 3, 2, 8, 1, 1, 5, 2, 6, 5, 9, 8, 8, 0, 3, 5, 4, 0, 1, 2, 6, 9, 8, 4, 7, 0, 1, 7, 0, 6, 0, 5, 1, 6, 8, 7, 6, 1, 6, 4, 9, 4, 7, 8, 1, 9, 2, 7, 5, 1, 4, 3, 8, 7, 6, 5, 3
Offset: 1
Examples
2.8032178560848059621034493264877253281152659880354...
Links
- Paolo Xausa, Table of n, a(n) for n = 1..10000
- Eric Weisstein's World of Mathematics, Triakis Icosahedron.
- Wikipedia, Triakis icosahedron.
Crossrefs
Programs
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Mathematica
First[RealDigits[ArcCos[-3*(8 + 5*Sqrt[5])/61], 10, 100]] (* or *) First[RealDigits[First[PolyhedronData["TriakisIcosahedron", "DihedralAngles"]], 10, 100]]
Formula
Equals arccos(-3*(8 + 5*sqrt(5))/61) = arccos(-3*(8 + 5*A002163)/61).
Comments