A378974 Decimal expansion of the volume of a triakis icosahedron with unit shorter edge length.

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

Offset

2,2

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 (19 + 13*sqrt(5))/4 = (19 + 13*A002163)/4.

Example

12.017220926874316513329814423376647765182009668737...

Mathematica

First[RealDigits[(19 + 13*Sqrt[5])/4, 10, 100]] (* or *)
First[RealDigits[PolyhedronData["TriakisIcosahedron", "Volume"], 10, 100]]

Crossrefs

Cf. A378973 (surface area), A378975 (inradius), A378976 (midradius), A378977 (dihedral angle).

Cf. A377695 (volume of a truncated dodecahedron with unit edge length).

Cf. A002163.

Sequence in context: A362787 A341200 A300130 * A101371 A325754 A154974

Adjacent sequences: A378971 A378972 A378973 * A378975 A378976 A378977

Keyword

nonn,cons,easy,new

Author

Paolo Xausa, Dec 14 2024

Status

approved