%I #10 Aug 23 2014 05:20:48
%S 6,9,4,8,1,9,3,0,0,8,6,6,7,3,0,5,3,6,2,6,7,1,9,2,7,5,0,6,2,0,3,5,2,5,
%T 1,2,7,7,0,2,1,1,6,9,6,8,6,7,2,4,4,1,5,2,8,8,9,4,4,2,3,3,8,9,0,2,6,6,
%U 9,5,9,2,3,9,8,3,0,6,5,4,5,6,1,0,6,6,5,9,6,4,6,1,4,3,9,8,0,3,3,9,9,6,6,2,4,3
%N Decimal expansion of a constant related to A173938.
%F Equals lim n -> infinity (A173938(n)/n!)^(1/n).
%F Root of the equation sqrt(2*Pi)*(erfi(1/sqrt(2)) + erfi((1/x-1)/sqrt(2))) = 2*exp(1/2).
%e 0.694819300866730536267192750620352512770211696867244152889...
%p evalf(solve(sqrt(2*Pi)*(erfi(1/sqrt(2)) + erfi((1/x-1)/sqrt(2))) = 2*exp(1/2),x),100)
%t RealDigits[x /.FindRoot[2*Sqrt[E] - Sqrt[2*Pi]*Erfi[1/Sqrt[2]] - Sqrt[2*Pi] * Erfi[(-1 + 1/x)/Sqrt[2]], {x, 1/2}, WorkingPrecision -> 120]][[1]]
%Y Cf. A173938.
%K nonn,cons
%O 0,1
%A _Vaclav Kotesovec_, Aug 23 2014