A379388 Decimal expansion of the midradius of a deltoidal hexecontahedron with unit shorter edge length.

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

Offset: 1

Author

Paolo Xausa, Dec 23 2024

Keywords

• nonn
• cons
• easy

Comments

The deltoidal hexecontahedron is the dual polyhedron of the (small) rhombicosidodecahedron.

Examples

			2.70344418537486330266596288467532955303640193...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Deltoidal Hexecontahedron.
• Wikipedia, Deltoidal hexecontahedron.
• Index entries for algebraic numbers, degree 2.

Crossrefs

Cf. A379385 (surface area), A379386 (volume), A379387 (inradius), A379389 (dihedral angle).

Cf. A377795 (midradius of a (small) rhombicosidodecahedron with unit edge length).

Cf. A010532.

Programs

Mathematica

First[RealDigits[5/4 + 13/Sqrt[80], 10, 100]] (* or *)
First[RealDigits[PolyhedronData["DeltoidalHexecontahedron", "Midradius"], 10, 100]]

PARI

5/4 + 13/(4*sqrt(5)) \\ Charles R Greathouse IV, Feb 05 2025

Formula

Equals 5/4 + 13/(4*sqrt(5)) = 5/4 + 13/A010532.