OFFSET
1,3
COMMENTS
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.
LINKS
Rick L. Shepherd, Table of n, a(n) for n = 1..20000
MathWorld, Deltoid
EXAMPLE
1.1968268412042980338198381798031456054275758934948039729977774890119737...
MATHEMATICA
RealDigits[N[3/Sqrt[2Pi], 105]] [[1]]
PROG
(PARI) default(realprecision, 120); 3/sqrt(2*Pi)
(Magma) SetDefaultRealField(RealField(100)); R:= RealField(); 3/Sqrt(2*Pi(R)); // G. C. Greubel, Sep 30 2018
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Rick L. Shepherd, Jan 16 2014
STATUS
approved