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

1,2

Comments

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

Links

Paolo Xausa, Table of n, a(n) for n = 1..10000

Index entries for algebraic numbers, degree 2.

Formula

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

Example

1.5606601717798212866012665431572735589272539065327...

Mathematica

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

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.

Sequence in context: A092161 A088602 A194347 * A021869 A340319 A103492

Adjacent sequences: A378390 A378391 A378392 * A378394 A378395 A378396

Keyword

nonn,cons,easy

Author

Paolo Xausa, Nov 30 2024

Status

approved