%I
%S 4,8,5,6,0,5,5,3,2,0,9,3,1,6,6,2,0,3,8,6,2,6,4,3,5,3,4,8,9,0,5,2,9,3,
%T 9,8,5,5,1,9,5,3,7,8,3,1,0,2,0,8,8,0,2,5,8,3,8,3,4,6,2,1,2,4,3,6,0,6,
%U 2,2,7,9,0,2,3,6,5,5,0,5,9,2,8,0,6,9,8,2,6,2,7,2,6,5,7,8,9,6,2,4,2,9
%N Decimal expansion of 'alpha', the threshold angle associated with the best constant in [a variation of] Hardy's inequality for a domain defined as a nonconvex plane sector of angle alpha.
%H Steven R. Finch, <a href="http://www.people.fas.harvard.edu/~sfinch/csolve/erradd.pdf">Errata and Addenda to Mathematical Constants</a>, p. 30.
%H Steven R. Finch, <a href="/A002193/a002193.pdf">Errata and Addenda to Mathematical Constants</a>, January 22, 2016. [Cached copy, with permission of the author]
%F alpha = Pi + 4*arctan(4*Gamma(3/4)^2/Gamma(1/4)^2).
%e 4.85605532093166203862643534890529398551953783102088...
%t alpha = Pi + 4*ArcTan[4*Gamma[3/4]^2/Gamma[1/4]^2]; RealDigits[alpha, 10, 102] // First
%o (PARI) Pi + 4*atan(4*gamma(3/4)^2/gamma(1/4)^2) \\ _Michel Marcus_, Sep 05 2014
%Y Cf. A068465, A068466.
%K nonn,cons,easy
%O 1,1
%A _JeanFrançois Alcover_, Sep 05 2014
