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%I #25 Sep 08 2022 08:45:59
%S 1,0,1,7,2,2,1,9,6,7,8,9,7,8,5,1,3,6,7,7,2,2,7,8,8,9,6,1,5,5,0,4,8,2,
%T 9,2,2,0,6,3,5,6,0,8,7,6,9,8,6,8,3,6,5,8,7,1,4,9,2,0,2,6,9,2,4,3,7,0,
%U 5,3,0,3,3,6,5,4,4,2,3,1,0,2,3,0,7,3,0,8,8,4,8,3,2,7,9,7,3,2,1,3
%N Decimal expansion of arctan(golden ratio).
%C The polar angle, in radians, of the cone circumscribed to a regular icosahedron from one of its vertices. - _Stanislav Sykora_, Feb 15 2014
%C The angle between the diagonal and the shorter side of a golden rectangle. - _Amiram Eldar_, May 18 2021
%H Stanislav Sykora, <a href="/A195723/b195723.txt">Table of n, a(n) for n = 1..2000</a>
%F Equals arccos(sqrt((5-sqrt(5))/10)). - _Stanislav Sykora_, Feb 15 2014
%F Equals Pi/2 - A195693. - _Amiram Eldar_, May 18 2021
%e arctan((1+sqrt(5))/2) = 1.0172219678978513677227...
%t r=GoldenRatio; N[ArcTan[r],100]
%t RealDigits[%] (* A195723 *)
%o (PARI) atan((1+sqrt(5))/2) \\ _G. C. Greubel_, Aug 20 2018
%o (Magma) SetDefaultRealField(RealField(100)); Arctan((1+Sqrt(5))/2); // _G. C. Greubel_, Aug 20 2018
%Y Cf. A001622, A195693, A243445.
%K nonn,cons,easy
%O 1,4
%A _Clark Kimberling_, Sep 23 2011
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