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A211269
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Integral of a sinc-shaped peak with unit height and unit half-height width.
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1
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8, 2, 8, 7, 0, 0, 1, 2, 0, 1, 2, 9, 0, 0, 3, 0, 6, 1, 8, 9, 6, 8, 6, 9, 3, 3, 6, 1, 7, 5, 9, 2, 3, 5, 8, 6, 3, 1, 8, 5, 3, 9, 5, 4, 2, 0, 6, 0, 5, 5, 9, 9, 0, 4, 1, 3, 2, 4, 7, 0, 9, 4, 1, 2, 0, 7, 5, 3, 6, 5, 6, 5, 0, 8, 0, 5, 9, 9, 1, 9, 6, 8, 8, 0, 6, 2, 0, 3, 2, 4, 3, 0, 6, 0, 9, 6, 8, 9, 6
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OFFSET
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0,1
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COMMENTS
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See first the general introduction in A211268.
This constant is the integral from -inf to +inf under a canonical sinc-shaped spectral peak S(x) defined by S(x)=sinc(2*x*eta), with sinc(z)=sin(z)/z, and eta=A199460, so that S(0)=1 and S(+1/2)=S(-1/2)=1/2.
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LINKS
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FORMULA
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EXAMPLE
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0.828700120129003061896869
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MATHEMATICA
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digits = 99; Pi/(2 FindRoot[x == 2*Sin[x], {x, 2}, WorkingPrecision -> digits+1] [[1, 2]]) // RealDigits[#, 10, digits]& // First (* Jean-François Alcover, Feb 20 2014 *)
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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