A386412 Decimal expansion of the surface area of an augmented truncated tetrahedron with unit edge.

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

Offset: 2

Author

Paolo Xausa, Jul 21 2025

Keywords

• nonn
• cons
• easy

Comments

The augmented truncated tetrahedron is Johnson solid J_65.

Examples

			14.258330249197702407928401219788170385128234149767...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 2..10000
• Wikipedia, Augmented truncated tetrahedron.

Crossrefs

Cf. A386411 (volume).

Cf. A010527.

Programs

Mathematica

First[RealDigits[3 + 13*Sqrt[3]/2, 10, 100]] (* or *)
First[RealDigits[PolyhedronData["J65", "SurfaceArea"], 10, 100]]

Formula

Equals 3 + 13*sqrt(3)/2 = 3 + 13*A010527.

Equals the largest root of 4*x^2 - 24*x - 471.