A377605 Decimal expansion of the midradius of a snub cube (snub cuboctahedron) with unit edge length.

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

Offset

1,2

Links

Table of n, a(n) for n=1..90.

Eric Weisstein's World of Mathematics, Snub Cube.

Wikipedia, Snub cube.

Index entries for algebraic numbers, degree 6.

Formula

Equals sqrt(1/(4*(2 - A058265))).

Example

1.2472231679936432517699189608980305834168701800...

Mathematica

First[RealDigits[Sqrt[1/(8 - 4*#)], 10, 100]] & [Root[#^3 - #^2 - # - 1 &, 1]] (* or *)
First[RealDigits[PolyhedronData["SnubCube", "Midradius"], 10, 100]]

Prog

(PARI) polrootsreal(64*x^6 - 112*x^4 + 20*x^2 - 1)[2] \\ Charles R Greathouse IV, Feb 11 2025

Crossrefs

Cf. A377602 (surface area), A377603 (volume), A377604 (circumradius).

Cf. A058265.

Sequence in context: A246183 A377731 A134974 * A244262 A166531 A133292

Adjacent sequences: A377602 A377603 A377604 * A377606 A377607 A377608

Keyword

nonn,cons,easy

Author

Paolo Xausa, Nov 03 2024

Status

approved