A232813 Decimal expansion of the minimum surface index of a closed cylinder.

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

Offset: 1

Author

Stanislav Sykora, Dec 03 2013

Keywords

• nonn
• cons
• easy

Comments

Equivalently, the minimum surface area among all closed cylinders (cans) enclosing a unit volume. It is attained when the cylinder is right circular and its height matches the diameter of its base. For evident reasons, this value should be called the 'cannery constant'. Its determination is a nice exercise in elementary analysis.

For a general definition of surface index, see A232808.

Examples

			5.53581044593208525729041163876696408034010879864785498817652692...
		

Links

• Stanislav Sykora, Table of n, a(n) for n = 1..1000
• Wikipedia, Cylinder (geometry).

Crossrefs

Cf. Other surface indices: A232808 (spheres), A232809, A232810, A232811, A232812 (platonic solids), A232814 (open cylinders), A232815 (closed cones), A232816 (open cones), A232817 (open tubes).

Programs

Mathematica

RealDigits[3 * Surd[2 * Pi, 3], 10, 120][[1]] (* Amiram Eldar, May 17 2023 *)

Formula

Equals (54*Pi)^(1/3) = 3*(2*Pi)^(1/3).