

A232814


Decimal expansion of the minimum surface index of a halfopen cylinder.


5



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

1,1


COMMENTS

Equivalently, the minimum external surface area among all pots or cups (halfopen cylinders) delimiting a unit volume. It is attained when the cylinder is right circular and its height matches the radius of its base. We might call it the 'cooking pot constant'. It minimizes the material needed to make the pot (and also its cooling rate). 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 3*Pi^(1/3) = 3*A092039.


EXAMPLE

4.3937756626845697890604275817913711752157905668838115230717678...


CROSSREFS

Cf. Other surface indices: A232808 (spheres), A232809, A232810, A232811, A232812 (platonic solids), A232813 (closed cylinders), A232815 (closed cones), A232816 (open cones), A232817 (open tubes).
Sequence in context: A276494 A236099 A155536 * A074123 A016704 A131896
Adjacent sequences: A232811 A232812 A232813 * A232815 A232816 A232817


KEYWORD

nonn,cons,easy


AUTHOR

Stanislav Sykora, Dec 04 2013


STATUS

approved



