Consider the affine Lie algebra $\mathfrak{g}$ associated with the simple Lie algebra $sl(n)$ consisting of $n\times n$ trace zero matrices over the field of complex numbers. For every dominant integral weight $\lambda$ there is a unique (upto isomorphism) irreducible highest weight $\mathfrak{g}$ module $V(\lambda)$. Although there are infinitely many weights of this module, certain important subclasses called the set of maximal dominant weights are finitely many.  In this talk we will show that for $\lambda = k\Lambda_0$ the multiplicities of these maximal dominant weights are given by the number of certain pattern avoiding permutations.

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