A378973 Decimal expansion of the surface area of a triakis icosahedron with unit shorter edge length.

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

Offset

2,1

Comments

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

Links

Paolo Xausa, Table of n, a(n) for n = 2..10000

Eric Weisstein's World of Mathematics, Triakis Icosahedron.

Wikipedia, Triakis icosahedron.

Formula

Equals 3*sqrt((173 - 9*sqrt(5))/2 = 3*sqrt((173 - 9*A002163)/2.

Example

26.228595976743751681458195104356801731865266699519...

Mathematica

First[RealDigits[3*Sqrt[(173 - 9*Sqrt[5])/2], 10, 100]] (* or *)
First[RealDigits[PolyhedronData["TriakisIcosahedron", "SurfaceArea"], 10, 100]]

Crossrefs

Cf. A378974 (volume), A378975 (inradius), A378976 (midradius), A378977 (dihedral angle).

Cf. A377694 (surface area of a truncated dodecahedron with unit edge length).

Cf. A002163.

Sequence in context: A064136 A347238 A171898 * A330541 A320575 A110218

Adjacent sequences: A378970 A378971 A378972 * A378974 A378975 A378976

Keyword

nonn,cons,easy,new

Author

Paolo Xausa, Dec 13 2024

Status

approved