Not a very golfable task. It is practically chosen such that the algorithm cannot be varied, and picking a better algorithm is what golf is really about. Not surprisingly my best entry is a variation on the initial attempt. Alternative approaches were only longer.

#        1         2         3         4         5         6         7
+         8
#234567890123456789012345678901234567890123456789012345678901234567890
+1234567890
for$a(1..pop){@_{map{sprintf"%.3f",$_[0]*$a/$_}1..$a}++}sort{$a<=>$b}k
+eys%_

grep!$_{$_}++,sort{$a<=>$b}map{$a=$_;map{sprintf"%.3f",$_[0]*$a/$_}1..
+$_}1..pop

my%y=map{$_=>[1..$_]}1..pop;@_{map{sprintf"%.3f",$_[0]*$a/$_}@$b}++whi
+le($a,$b)=each%y;sort{$a<=>$b}keys%_
[download]

Makeshifts last the longest.