It depends on the specific school’s math department and its offerings.
It also depends on the student. A super-advanced student in math may find that an undergraduate-only school like many liberal arts colleges may not offer the graduate level course work and research opportunities that may exist at a PhD-granting school. “Super-advanced” in this context means having completed college math course work beyond the calculus 1-2 (or AP calculus BC) level while in high school; such a student is likely to want to take graduate level math courses as an undergraduate if s/he majors in math.