A381264 Decimal expansion of the edge length of the dodecahedron inside a circumscribed unit sphere.

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

Offset: 0

Author

R. J. Mathar, Feb 18 2025

Keywords

• nonn
• cons

Examples

			0.7136441795461798638839396860921757479633721504937...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 0..10000
• Wikipedia, Regular Dodecahedron.

Crossrefs

Cf. A156547, A001622, A179296.

Programs

Maple

g := (1+sqrt(5))/2 ; Digits := 100 ; evalf(2/sqrt(3)/g) ;

Mathematica

First[RealDigits[2/(Sqrt[3]*GoldenRatio), 10, 100]] (* Paolo Xausa, Feb 19 2025 *)

Formula

Equals 2/(sqrt(3)*A001622) = 1/A179296.

Equals 2*sin(A156547/2).

Minimal polynomial: 9*x^4 - 36*x^2 + 16. - Amiram Eldar, Feb 26 2025