<p>Just off the top of my head: Penn, Reed and Brown.</p>
<p><a href=“http://economics.sas.upenn.edu/undergraduate-program/mathematical-economics-major”>http://economics.sas.upenn.edu/undergraduate-program/mathematical-economics-major</a>
<a href=“http://www.reed.edu/catalog/programs/interdis_majors/mathecon.html”>http://www.reed.edu/catalog/programs/interdis_majors/mathecon.html</a>
<a href=“http://bulletin.brown.edu/the-college/concentrations/maec/”>http://bulletin.brown.edu/the-college/concentrations/maec/</a></p>
<p>Most schools require a full double major.</p>