pan>
<span class="r-out co"><span class="r-pr">#&gt;</span> 3 "(1/14)a+(5/28)b+(5/14)c"  "(3/7)a+(5/14)b" </span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 4 "(1/70)a+(1/14)b+(3/14)c"  "(8/35)a+(2/7)b" </span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 5 "(1/56)b+(3/28)c"          "(1/14)a+(5/28)b"</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 6 "(1/28)c"                  "(1/14)b"        </span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 7 "0"           