A385259 Decimal expansion of the surface area of a gyroelongated square bicupola with unit edge.

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

Offset

2,1

Comments

The gyroelongated square bicupola is Johnson solid J_45.

Links

Paolo Xausa, Table of n, a(n) for n = 2..10000

Wikipedia, Gyroelongated square bicupola.

Index entries for algebraic numbers, degree 2.

Formula

Equals 10 + 6*sqrt(3) = 10 + 6*A002194.

Equals the largest root of x^2 - 20*x - 8.

Example

20.392304845413263761164678049035234201656831522862...

Mathematica

First[RealDigits[10 + 6*Sqrt[3], 10, 100]] (* or *)
First[RealDigits[PolyhedronData["J45", "SurfaceArea"], 10, 100]]

Prog

(PARI) 10 + 6*sqrt(3) \\ Charles R Greathouse IV, Oct 10 2025

Crossrefs

Cf. A385258 (volume).

Cf. A002194, A179588, A384215, A385257.

Sequence in context: A255384 A236396 A251592 * A365985 A327244 A325816

Adjacent sequences: A385256 A385257 A385258 * A385260 A385261 A385262

Keyword

nonn,cons,easy

Author

Paolo Xausa, Jun 26 2025

Status

approved