A378393 Decimal expansion of the midradius of a deltoidal icositetrahedron with unit shorter edge length.

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

Offset: 1

Author

Paolo Xausa, Nov 30 2024

Keywords

• nonn
• cons
• easy

Comments

The deltoidal icositetrahedron is the dual polyhedron of the (small) rhombicuboctahedron.

Examples

			1.5606601717798212866012665431572735589272539065327...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000
• Index entries for algebraic numbers, degree 2.

Crossrefs

Cf. A378390 (surface area), A378391 (volume), A378392 (inradius), A378394 (dihedral angle).

Cf. A285871 (midradius of a (small) rhombicuboctahedron with unit edge).

Cf. A010474, A093577.

Programs

Mathematica

First[RealDigits[(2 + Sqrt[18])/4, 10, 100]] (* or *)
First[RealDigits[PolyhedronData["DeltoidalIcositetrahedron", "Midradius"], 10, 100]]

Formula

Equals (2 + 3*sqrt(2))/4 = (2 + A010474)/4.