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A242440 Decimal expansion of a constant related to a certain Sobolev isoperimetric inequality. 2
3, 1, 8, 7, 5, 9, 0, 6, 0, 9, 8, 0, 3, 8, 6, 6, 2, 4, 8, 1, 1, 9, 7, 2, 1, 7, 2, 4, 7, 6, 2, 1, 2, 5, 4, 3, 2, 2, 5, 3, 5, 0, 7, 7, 4, 6, 9, 9, 6, 8, 2, 2, 8, 2, 9, 0, 2, 1, 4, 1, 8, 1, 5, 8, 1, 8, 8, 7, 8, 8, 4, 7, 0, 3, 8, 3, 9, 9, 7, 6, 8, 0, 8, 1, 6, 0, 2, 0, 4, 6, 3, 9, 3, 3, 8, 8, 2, 9, 1, 3 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
Summarizing the definition: the supremum of the absolute value of a differentiable function f(x,y) is less than or equal to 0.318759... times the square root of the integral of the sum of squares of all partial derivatives of f.
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, p. 222.
LINKS
FORMULA
Equals sqrt( 1/(2*Pi) * Integral_{t >= 1} 1/(sqrt(t^2 + 2)*sqrt(t^2 + 3)) dt ).
sqrt((F(log(3)/2*i, 3/2)*i + K(-1/2))/(2*Pi*sqrt(2))), with i = sqrt(-1), F and K being the elliptic integrals.
EXAMPLE
0.31875906098038662481197217247621254322535...
MAPLE
Re(evalf(sqrt((EllipticF(I/sqrt(3), sqrt(3/2))*I + EllipticK(I/sqrt(2))) / (2*Pi*sqrt(2))), 120)); # Vaclav Kotesovec, Apr 22 2015
MATHEMATICA
Sqrt[(EllipticF[Log[3]/2*I, 3/2]*I + EllipticK[-1/2])/(2*Pi*Sqrt[2])] // Re // RealDigits[#, 10, 100]& // First
RealDigits[Sqrt[(EllipticK[1/3] - EllipticF[ArcCot[Sqrt[2]], 1/3])/(2 Sqrt[3] Pi)], 10, 100][[1]] (* Jan Mangaldan, Jan 04 2017 *)
CROSSREFS
Sequence in context: A257142 A270861 A208656 * A245651 A007023 A176103
KEYWORD
nonn,cons
AUTHOR
STATUS
approved

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Last modified March 28 14:38 EDT 2024. Contains 371254 sequences. (Running on oeis4.)