Correct me if I'm wrong, but isn't it this?

I think you're thinking of e

^{x²}.

Anyway, every function can be integrated, it's just that not all of them can be integrated algebraically.

If you wanted to find ∫e

^{x²}dx, you'd need to take each and every real value of x and work out the integral at that point using numerical methods. I'd advise telling a computer to do it.