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

1,1

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.

Links

Stanislav Sykora, Table of n, a(n) for n = 1..1000

Wikipedia, Cylinder (geometry).

Formula

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

Example

5.53581044593208525729041163876696408034010879864785498817652692...

Mathematica

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

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).

Sequence in context: A089486 A199617 A195693 * A267033 A306982 A278928

Adjacent sequences: A232810 A232811 A232812 * A232814 A232815 A232816

Keyword

nonn,cons,easy

Author

Stanislav Sykora, Dec 03 2013

Status

approved