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A232815
Decimal expansion of the minimum surface index of a closed cone.
5
6, 0, 9, 2, 9, 4, 7, 7, 8, 5, 3, 7, 9, 5, 5, 5, 6, 0, 3, 4, 3, 6, 3, 1, 6, 0, 0, 8, 9, 4, 8, 7, 5, 6, 9, 3, 6, 9, 1, 0, 7, 6, 1, 5, 1, 5, 0, 4, 7, 2, 0, 7, 1, 7, 3, 2, 1, 3, 0, 5, 2, 1, 5, 2, 9, 0, 1, 1, 2, 8, 0, 7, 0, 2, 4, 1, 1, 7, 9, 6, 0, 6, 9, 6, 2, 2, 1, 2, 0, 4, 7, 0, 7, 6, 5, 6, 3, 9, 1, 8, 0, 0, 3, 2, 6
OFFSET
1,1
COMMENTS
Equivalently, minimum surface area among all closed cones enclosing a unit volume. It is attained when the cone is right circular and its height equals the diameter of its base multiplied by sqrt(2). Considering one of the ways of marketing ice cream, we might call it the "frozen cone constant".
For a general definition of surface index, see A232808.
LINKS
Wikipedia, Cone
FORMULA
Equals (72*Pi)^(1/3) = 6*(Pi/3)^(1/3).
EXAMPLE
6.0929477853795556034363160089487569369107615150472...
MATHEMATICA
RealDigits[Surd[72*Pi, 3], 10, 120][[1]] (* Harvey P. Dale, Jul 13 2015 *)
CROSSREFS
Cf. Other surface indices: A232808 (spheres), A232809, A232810, A232811, A232812 (platonic solids), A232813 (closed cylinders), A232814 (open cylinders), A232816 (open cones), A232817 (open tubes).
Sequence in context: A331239 A324008 A248681 * A323606 A133077 A200124
KEYWORD
nonn,cons,easy
AUTHOR
Stanislav Sykora, Dec 04 2013
STATUS
approved