Ira Gessel's user avatar
Ira Gessel's user avatar
Ira Gessel's user avatar
Ira Gessel
  • Member for 13 years, 4 months
  • Last seen this week
  • Brandeis University, Waltham, MA, United States
13 votes

Combinatorial identities

12 votes

Exponential of a specific hypergeometric series

12 votes

Interpolating a sum of binomial coefficients using a sin function

12 votes

The proportion between permutations and derangements.

12 votes
Accepted

"MultiCatalan numbers"

12 votes

A recurrence relation on Catalan numbers

12 votes
Accepted

A combinatorial identity involving harmonic numbers

12 votes

A combinatorial identity

12 votes

Series involving power of the index

12 votes
Accepted

Help finding an analytic continuation

12 votes
Accepted

A combinatorial interpretation for $n$-ary trees for negative $n$

11 votes

Positivity of a one-variable rational function

10 votes

Asking for a proof for a sum of products of binomials: an "interesting" identity?

10 votes
Accepted

Double q-analog of Pochhammer

10 votes
Accepted

Identity with Pochhammer and harmonic numbers

10 votes

Prominent non-mathematical work of mathematicians

10 votes
Accepted

Sum of products of exponentials and polynomials

10 votes

Counting card distributions when cards are duplicated

10 votes

Faà di Bruno's formula for inverse functions?

9 votes

Identity for Power Series and Binomial Coefficients

9 votes
Accepted

Congruence for complementary Bell numbers

9 votes

Combinatorial counting with symmetry

9 votes

Method to evaluate an infinite sum of ratio of Gamma functions (how does Mathematica do it?)

9 votes
Accepted

Explicit formula for a generating function

9 votes
Accepted

Generating function for "descents" and "cycle-types", in tandem

9 votes
Accepted

A sequence of polynomials related to Catalan numbers

8 votes
Accepted

Infinite sum of Laguerre polynomials: is $\sum_{k=0}^{\infty}\frac{n!}{(k+n)!}x^kL_n^k(x)^2=e^x+P(x)$, with $P$ a polynomial of degree $2n-1$?

8 votes
Accepted

Finite sum with falling factorial

8 votes

What are some bases of the polynomial ring that expand positively in the basis of binomial coefficients?

8 votes
Accepted

What is the generalization of the formula for Chung and Feller's Theorem 2 to odd numbers of steps?

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