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Refined Eulerian numbers and ballot permutations

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 نشر من قبل Tongyuan Zhao
 تاريخ النشر 2021
  مجال البحث
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A ballot permutation is a permutation {pi} such that in any prefix of {pi} the descent number is not more than the ascent number. In this article, we obtained a formula in close form for the multivariate generating function of {A(n,d,j)}, which denote the number of permutations of length n with d descents and j as the first letter. Besides, by a series of calculations with generatingfunctionology, we confirm a recent conjecture of Wang and Zhang for ballot permutations.



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