https://accounts.google.com/ServiceLogin?service=oz&passive=1209600&continue=https%3A%2Fplus.google.com%2F%3Fgpsrc%3Dgplp0&partnerid=gplp0&followup=https%3A%2Fplus.google.com%2F%3Fgpsrc%3Dgplp0

This URL has not been tested yet.