7 search results - page 1 / 2 » Enumeration of permutations by number of alternating descent... |
EJC
2007
13 years 4 months ago
2007
We consider in this work the enumeration of involutions by descent sets, and based on that, by descent numbers. Formulas of the number of involutions with a prescribed descent set...
CORR
2010
Springer
13 years 2 months ago
2010
Springer
We suggest an approach for the enumeration of minimal permutations having d descents which uses skew Young tableaux. We succeed in finding a general expression for the number of s...
COMBINATORICS
1998
13 years 4 months ago
1998
Using Zeilberger’s factorization of two-stack-sortable permutations, we write a functional equation — of a strange sort — that defines their generating function according t...
EJC
2010
13 years 5 months ago
2010
A classical result of Euler states that the tangent numbers are an alternating sum of Eulerian numbers. A dual result of Roselle states that the secant numbers can be obtained by a...
JCT
2011
12 years 11 months ago
2011
The Baxter number Bn can be written as Bn = n k=0 Θk,n−k−1 with Θk,ℓ = 2 (k + 1)2 (k + 2) k + ℓ k k + ℓ + 1 k k + ℓ + 2 k . These numbers have first appeared in the...