def first_on_page(self, page_number):
        page_number = self.validate_page_number(page_number)
        return (self.num_per_page * page_number) + 1
Returns the 1-based index of the first object on the given page,
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-0.96/django/core/paginator.py/ObjectPaginator.first_on_page