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%I #9 Feb 06 2022 07:00:50
%S 7,7,9,8,9,3,4,0,0,3,7,6,8,2,2,8,2,9,4,7,4,2,0,6,4,1,3,6,5,2,6,9,0,1,
%T 3,6,6,3,0,6,2,5,7,0,8,1,3,6,3,2,0,9,6,0,1,0,3,1,3,3,5,8,3,1,7,8,0,7,
%U 1,7,6,0,9,7,9,1,0,8,8,9,0,1,0,8,7,7,8,7,0,7,3,0,5,2,7,8,5,2,8,1,5,8,9,8,9
%N Decimal expansion of the Fresnel cosine integral function at 1.
%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/FresnelIntegrals.html">Fresnel Integrals</a>.
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Fresnel_integral">Fresnel integral</a>.
%F From _Amiram Eldar_, Feb 06 2022: (Start)
%F Equals Integral_{x=0..1} cos(Pi*x^2/2) dx.
%F Equals Sum_{k>=0} (-1)^k * (Pi/2)^(2*k)/((2*k)!*(4*k + 1)). (End)
%e 0.77989340037682282947420641365269013663062570813632...
%t RealDigits[ FresnelC[1], 10, 105][[1]]
%o (PARI) intnum(x=0, 1, cos(Pi*x^2/2)) \\ _Michel Marcus_, Feb 06 2022
%Y Cf. A099289.
%K cons,nonn
%O 0,1
%A _Robert G. Wilson v_, Oct 11 2004