String concat with cfscript in cfloop

Question

I need to concat string in cfloop with cfscript. I have this code but it didn't work:

conf = {};

array = [3,2,1];

for (i=1; i <= arrayLen(array);i=i+1) {
  writeOutput(array[i]);

  conf.user_ & [i] = [i]; // this line didn't work          
}

writeDump(var="#conf#")
abort;

What I need :

Please assist me. Thanks in advance