Cannot resolve $var in awk

My script
----------

for i in `cat n`;do
export k=`echo "CSN: "$i`       //combining CSN: and value from n
echo "$k"
awk ''{print "CSN: "$0;}'{_=29}_&&_--' file1|tail -1 >> file2
done

In the above script i cannot able to resolve $k in awk command
file n contains
------------
0000
1111
2222
3333
4444
6666

I am trying to append CSN: 0000 and search it in the file1 and
display the 29th line from the searched pattern