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A211269 Integral of a sinc-shaped peak with unit height and unit half-height width. 1
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 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

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.

LINKS

Table of n, a(n) for n=0..98.

FORMULA

pi/(2*A199460)

EXAMPLE

0.828700120129003061896869

MATHEMATICA

digits = 99; Pi/(2 FindRoot[x == 2*Sin[x], {x, 2}, WorkingPrecision -> digits+1] [[1, 2]]) // RealDigits[#, 10, digits]& // First (* Jean-Fran├žois Alcover, Feb 20 2014 *)

CROSSREFS

Cf. A199460, A211268.

Sequence in context: A163960 A246849 A143531 * A278809 A278261 A019865

Adjacent sequences:  A211266 A211267 A211268 * A211270 A211271 A211272

KEYWORD

nonn,cons,easy

AUTHOR

Stanislav Sykora, Apr 07 2012

STATUS

approved

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Last modified June 23 18:12 EDT 2017. Contains 288668 sequences.