
co.combinatorics - Sum of combinations - MathOverflow
If you are interested in approximations to your ratios, you may find the accepted answer (and some comments of mine) to this MathOverflow post useful: Sum of 'the first k' binomial coefficients for fixed …
Important formulas in combinatorics - MathOverflow
Aug 17, 2015 · Zaslavsky's formula is a very important formula in enumerative combinatorics, as well as geometric combinatorics, and the basis for important developments in topological combinatorics.
Combinations of multisets with finite multiplicities
In addition to the OP's 2011 paper with Ž. Jurić: A New Formula for the Number of Combinations of Permutations of Multisets Applied Mathematical Sciences, Vol. 5, 2011, no. 18, 875-881 there is a …
Combination formula of $ (-1)^ {n-1}2 (n-1)!$ - MathOverflow
Feb 17, 2025 · How to prove that $$\\sum_{b=0}^{[\\frac{n}{2}]}(-1)^{n-b-1}(n-b-1)!\\binom{n}{n-2b}\\frac{\\binom{2b}{2}\\binom{2b-2}{2}\\dots \\binom{2}{2}}{b!}2^{n-b}$$ equals ...
Sum of 'the first $k$' binomial coefficients for fixed $N$
One can take this a step further. In addition to combining pairs of terms of the original sum N choose i to get a sum of terms of the form N+1 choose 2j+c, where c is always 0 or always 1, one can now take …
Combination with repetition with limit - MathOverflow
First component (for i = 0) is just a regular combination with repetition, then I subtract all that have at least 1 box overfilled, then I need to add those that have at least 2 box overfilled (since earlier I …
Creating a combinations with unique sets - MathOverflow
I am trying a variation of non-repetitive combination scenario. I can use the formula n!/r!x (n-r)! to find non-repetitive combinations of size "r" from "n" numbers.
Combinatorial\Probabilistic Proof of Stirling's Approximation
The Wikipedia page List of probabilistic proofs of non-probabilistic theorems has a reference to the paper: Blyth, Colin R.; Pathak, Pramod K. A Note on Easy Proofs of Stirling's Theorem. Amer. Math. …
Inverting the Weyl Character Formula - MathOverflow
Apr 2, 2010 · The Weyl character formula tells us how to go from the former to the latter. My question is: is there much known about the matrix of going from the latter to the former? I've gone through a few …
An identity involving a product of two binomial coefficients
Oct 26, 2015 · Rather than expressing this as a linear combination with of $1,n,n^2,\cdots,n^ {2q}$ with rational coefficients, it is better to express it as a linear combination of $\binom {n} {0},\binom {n} …