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A232814
Decimal expansion of the minimum surface index of a half-open 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
OFFSET
1,1
COMMENTS
Equivalently, the minimum external surface area among all pots or cups (half-open 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
FORMULA
Equals 3*Pi^(1/3) = 3*A092039.
EXAMPLE
4.3937756626845697890604275817913711752157905668838115230717678...
MATHEMATICA
RealDigits[3 * Surd[Pi, 3], 10, 120][[1]] (* Amiram Eldar, May 17 2023 *)
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).
Cf. A092039.
Sequence in context: A276494 A236099 A155536 * A074123 A016704 A131896
KEYWORD
nonn,cons,easy
AUTHOR
Stanislav Sykora, Dec 04 2013
STATUS
approved