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%I #14 Oct 01 2022 14:16:00
%S 1,1,9,6,8,2,6,8,4,1,2,0,4,2,9,8,0,3,3,8,1,9,8,3,8,1,7,9,8,0,3,1,4,5,
%T 6,0,5,4,2,7,5,7,5,8,9,3,4,9,4,8,0,3,9,7,2,9,9,7,7,7,7,4,8,9,0,1,1,9,
%U 7,3,7,7,7,6,9,7,9,0,5,5,1,5,5,0,3,7,5,7,0,0,1,7,2,1,9,2,0,8,0,9,2,9,0,9,0
%N Decimal expansion of 3/sqrt(2*Pi).
%C The radius of the large circle, the a-value in the MathWorld link, of a deltoid (3-cusped hypocycloid) with area 1. Thus, for any r > 0, this particular a*sqrt(r) is the radius of the large circle of a deltoid with area r. The radius of the small circle is a*sqrt(r)/3 = A231863*sqrt(r), because A231863 is the radius of the small circle, the b-value in the MathWorld link, of a deltoid with area 1.
%H Rick L. Shepherd, <a href="/A235916/b235916.txt">Table of n, a(n) for n = 1..20000</a>
%H MathWorld, <a href="http://mathworld.wolfram.com/Deltoid.html">Deltoid</a>
%H <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>
%F 3/sqrt(2*Pi) = 3/A019727 = 3*A231863 = 1/A019728.
%e 1.1968268412042980338198381798031456054275758934948039729977774890119737...
%t RealDigits[N[3/Sqrt[2Pi],105]] [[1]]
%o (PARI) default(realprecision, 120); 3/sqrt(2*Pi)
%o (Magma) SetDefaultRealField(RealField(100)); R:= RealField(); 3/Sqrt(2*Pi(R)); // _G. C. Greubel_, Sep 30 2018
%Y Cf. A019727, A019728, A231863 (corresponding small circle radius).
%K nonn,cons
%O 1,3
%A _Rick L. Shepherd_, Jan 16 2014