<project name="n" default="main">
  <target name="main">
    <property id="1" name="p" value="v"/>
    <property name="p1" value="1"/>
    <property name="p2" value="${p1}"/>
    <property name="p3" value="${p2}"/>
    <property name="p4" value="${p3}"/>
    <echo refid="<ref>${p4}" message="${p}"/>
  </target>
</project>