### integral interpretation

I found an integral which sage doesn't much seem to like:

var('R, t')
integral(((1/(R*t))*exp(i*R*t)), t)
it returns this: (essentially)
(Ei(iRt))/R

But the two i's should just multiply out and the two R's simplify to 1.
And what's 'E'?
I realize the integral is divergent, and the indefinite serves my purposes, but I'm not quite sure what