A385257 Decimal expansion of the surface area of a gyroelongated triangular bicupola with unit edge.

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

Offset

2,2

Comments

The gyroelongated triangular bicupola is Johnson solid J_44.

Links

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

Wikipedia, Gyroelongated triangular bicupola.

Index entries for algebraic numbers, degree 2.

Formula

Equals 6 + 5*sqrt(3) = 6 + 5*A002194 = 6 + 10*A010527.

Equals the largest root of x^2 - 12*x - 39.

Example

14.660254037844386467637231707529361834714026269...

Mathematica

First[RealDigits[6 + 5*Sqrt[3], 10, 100]] (* or *)
First[RealDigits[PolyhedronData["J44", "SurfaceArea"], 10, 100]]

Prog

(PARI) 6 + sqrt(75) \\ Charles R Greathouse IV, Oct 10 2025

Crossrefs

Cf. A385256 (volume).

Cf. A002194, A010527.

Essentially the same of A332133, A375193 and A010527.

Sequence in context: A301915 A009456 A009465 * A324942 A199161 A373793

Adjacent sequences: A385254 A385255 A385256 * A385258 A385259 A385260

Keyword

nonn,cons,easy

Author

Paolo Xausa, Jun 24 2025

Status

approved