I form a multiset of symbols of size $n$:
ASDFJLAWEN
There are an infinite number of distinct symbols to choose from. Because it is a multiset, order does not matter. All that matters is the number of "distinct" symbols.
So JCKL is the same as ENOH because in each case there are four distinct symbols. AABJ is the same as KBBO because in each case there are three distinct symbols, two of which are the same.
ABAB is not the same as QQQL.
What is the number of such multisets?