OFFSET
0,1
FORMULA
Equals lim n -> infinity (A173938(n)/n!)^(1/n).
Root of the equation sqrt(2*Pi)*(erfi(1/sqrt(2)) + erfi((1/x-1)/sqrt(2))) = 2*exp(1/2).
EXAMPLE
0.694819300866730536267192750620352512770211696867244152889...
MAPLE
evalf(solve(sqrt(2*Pi)*(erfi(1/sqrt(2)) + erfi((1/x-1)/sqrt(2))) = 2*exp(1/2), x), 100)
MATHEMATICA
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]]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Vaclav Kotesovec, Aug 23 2014
STATUS
approved