A new class of multiset Wilf equivalent pairs

We say the pair of patterns (σ,τ)(σ,τ) is multiset Wilf equivalent if, for any multiset M, the number of permutations of M   that avoid σσ is equal to the number of permutations of M   that avoid ττ. In this paper, we find a large new class of multiset Wilf equivalent pairs, namely, the pair (σn-2(n-1)nσn-2(n-1)n, σn-2n(n-1)σn-2n(n-1)), for n⩾3n⩾3 and σn-2σn-2 a permutation of {1x1,2x2,…,(n-2)xn-2}{1x1,2x2,…,(n-2)xn-2}. It is the most general multiset Wilf equivalence result to date.