This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A235916 #15 Feb 16 2025 08:33:21 %S A235916 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 A235916 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 A235916 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 A235916 Decimal expansion of 3/sqrt(2*Pi). %C A235916 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 A235916 Rick L. Shepherd, <a href="/A235916/b235916.txt">Table of n, a(n) for n = 1..20000</a> %H A235916 MathWorld, <a href="https://mathworld.wolfram.com/Deltoid.html">Deltoid</a> %H A235916 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a> %F A235916 3/sqrt(2*Pi) = 3/A019727 = 3*A231863 = 1/A019728. %e A235916 1.1968268412042980338198381798031456054275758934948039729977774890119737... %t A235916 RealDigits[N[3/Sqrt[2Pi],105]] [[1]] %o A235916 (PARI) default(realprecision, 120); 3/sqrt(2*Pi) %o A235916 (Magma) SetDefaultRealField(RealField(100)); R:= RealField(); 3/Sqrt(2*Pi(R)); // _G. C. Greubel_, Sep 30 2018 %Y A235916 Cf. A019727, A019728, A231863 (corresponding small circle radius). %K A235916 nonn,cons %O A235916 1,3 %A A235916 _Rick L. Shepherd_, Jan 16 2014