OFFSET
1,1
COMMENTS
See A276762 for the real part, as well as detailed comments and links.
LINKS
Stanislav Sykora, Table of n, a(n) for n = 1..2000
EXAMPLE
2.06592220237066218898810461125410843001424985319006732838579118...
MATHEMATICA
RealDigits[Im[z/.FindRoot[LogIntegral[z] == z, {z, 2+I}, WorkingPrecision -> 100]]][[1]] (* Vaclav Kotesovec, Oct 30 2016 *)
PROG
(PARI) \\ z may be t_INT, t_REAL, or t_COMPLEX except 0 or 1
li(z)=
{
my(sgn=(-1)^if(real(z)<1, imag(z)<0, imag(z)<=0));
sgn*Pi*I - eint1(-log(z));
}
default(realprecision, 2100); \\ Execution:
Eps_= 4.0*10.0^(-default(realprecision));
z=1+I; zlast=0; \\ Initialize and iterate
for(k=1, 1e6, z=li(z); if(abs(z-zlast)<Eps_, break); zlast=z);
imag(z) \\ Display the result
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Stanislav Sykora, Oct 28 2016
STATUS
approved