A378975 Decimal expansion of the inradius of a triakis icosahedron with unit shorter edge length.

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

Offset

1,2

Comments

The triakis icosahedron is the dual polyhedron of the truncated dodecahedron.

Links

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

Eric Weisstein's World of Mathematics, Triakis Icosahedron.

Wikipedia, Triakis icosahedron.

Formula

Equals sqrt((477 + 199*sqrt(5))/488) = sqrt((477 + 199*A002163)/488).

Example

1.37451744701047164727510000639742367448102733307...

Mathematica

First[RealDigits[Sqrt[(477 + 199*Sqrt[5])/488], 10, 100]] (* or *)
First[RealDigits[PolyhedronData["TriakisIcosahedron", "Inradius"], 10, 100]]

Crossrefs

Cf. A378973 (surface area), A378974 (volume), A378976 (midradius), A378977 (dihedral angle).

Cf. A002163.

Sequence in context: A267412 A087941 A278389 * A021271 A238274 A094689

Adjacent sequences: A378972 A378973 A378974 * A378976 A378977 A378978

Keyword

nonn,cons,easy,new

Author

Paolo Xausa, Dec 14 2024

Status

approved