5 citations · 7 across the 4 of their papers we have counts for
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Restricted 132-avoiding permutations
T. Mansour, A. Vainshtein
We study generating functions for the number of permutations on n letters avoiding 132 and an arbitrary permutation on k letters, or containing exactly once. In several int…
Restricted permutations and Chebyshev polynomials
T. Mansour, A. Vainshtein
We study generating functions for the number of permutations in $\SS_n$ subject to two restrictions. One of the restrictions belongs to $\SS_3$, while the other to $\SS_k$. It turn…
Layered restrictions and Chebyshev polynomials
T. Mansour, A. Vainshtein
A permutation is called layered if it consists of the disjoint union of substrings (layers) so that the entries decrease within each layer, and increase between the layers. We find…
Avoiding maximal parabolic subgroups of S_k
Toufik Mansour, Alek Vainshtein
We find an explicit expression for the generating function of the number of permutations in S_n avoiding a subgroup of S_k generated by all but one simple transpositions. The gener…