A386000 Decimal expansion of the volume of a tridiminished icosahedron with unit edge.

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

Offset: 1

Author

Paolo Xausa, Jul 14 2025

Keywords

• nonn
• cons
• easy

Comments

The tridiminished icosahedron is Johnson solid J_63.

Examples

			1.277186493437438661452675653379955568670180...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000
• Wikipedia, Tridiminished icosahedron.

Crossrefs

Cf. A386001 (surfacea area).

Cf. A002163, A020829, A102208, A179552, A385857, A386002.

Programs

Mathematica

First[RealDigits[5/8 + 7*Sqrt[5]/24, 10, 100]] (* or *)
First[RealDigits[PolyhedronData["J63", "Volume"], 10, 100]]

Formula

Equals 5/8 + 7*sqrt(5)/24 = 5/8 + 7*A002163/24.

Equals A102208 - 3*A179552 = A386002 - A020829.

Equals the largest root of 144*x^2 - 180*x - 5.