Skip to main content
Ira Gessel's user avatar
Ira Gessel's user avatar
Ira Gessel's user avatar
Ira Gessel
  • Member for 14 years, 1 month
  • Last seen this week
  • Brandeis University, Waltham, MA, United States
Loading…
comment
Bijective proof of deteminant formula for Hankel matrix of central binomial coefficients
I haven't checked all the details but I think you can do this using the fact that $\binom{2n}{n}$ counts Dyck paths of length $2n$ in which up steps starting at height 0 are weighted by 2. This fact corresponds, via Flajolet's combinatorial approach to continued fractions, to the continued fraction $$ \frac{1}{\sqrt{1-4x}}= \cfrac{1}{1-\cfrac{2 x}{1-\cfrac{x}{1-\cfrac{x}{1-\cfrac{x}{1-\cfrac{x}{1-\dots}}}}}} $$
Loading…
comment
Low-level proof of identity related to Weierstrass P-function
Some people use the word "combinatorial" for anything to do with (formal) power series. Other people call such things "analytic."
comment
Recursion for the Chebyshev transform of $m^n$
It might help if you defined Chebyshev transform.
comment
comment
Examples when quantum $q$ equals to arithmetic $q$
For an explanation of the connection between $q$ as a variable and as a prime power in $q$-binomial coefficients, see D. E. Knuth's paper, Subspaces, subsets, and partitions, doi.org/10.1016/0097-3165(71)90022-7.
awarded
awarded
comment
A closed form (or tight upper bound) for $\sum_{j=0}^{2m} (-1)^j (m-j)^{2m+2k} \binom{2m}{j}$
Dividing these numbers by $(2m)!$ gives the central factorial numbers of the second kind, oeis.org/A036969 and oeis.org/A008957.
comment
Unpacking the plethystic substitution $h_n[n\mathbf{z}]$ in a paper by Aval, Bergeron and Garsia
$h_k[n\mathbf{z}]$ is the coefficient of $t^k$ in $(1+h_1t + h_2t^2+\cdots)^n$. This agrees with your examples for $k=n=4$ and $k=n=5$.
answered
Loading…
awarded
answered
Loading…
answered
Loading…
revised
Recreation with Catalan
Added update.
Loading…
answered
Loading…
Loading…
revised
Loading…
answered
Loading…
1 2
3
4 5
42