Why should be accept this ${\displaystyle {n \choose k}}=0 $ for $k> n$?
9009
$n$ choose $k$ where $n$ is less than $k$
47670
Algebraic proof of $\sum_{i=0}^k{{n \choose i}{m \choose {k-i}}}= {{m+n}\choose k}$
2708
Inequality ${n \choose k} \leq \left(\frac{en}{ k}\right)^k$
104704
Evaluate $\sum\limits_{k=0}^n \binom{n}{k}$ combinatorially
27025
How do I choose an element from a non-empty set?
89279
If $\sum a_n/k^n = 0$ for all $k$, then $a_n = 0$ for all $n$
84394
Choice function for a collection of nonempty subsets of $\{0,1\}^\omega$
2857
How do I pass an unknown value to a choice key in pgfkeys?
2396
Order-preserving injections of ordinals into $[0,1]$
123955
How to compute $\sum\limits_{k=0}^n (-1)^k{2n-k\choose k}$?
11928
Why isn't "k" incremented in the statement "m = ++i && ++j || ++k" when "++i&&++j" evaluates to true?
62996
A problem regarding the proof of ${p^nk\choose p^n}\equiv k\mod p$, where $p\nmid k$.
122800
Let $a > 0$ and let $k \in \mathbb{N}$. Evaluate the limit
65467
ElGamal in private set intersection: how to handle negative numbers?
81527
Graphics Function Definition Style (Using SubValues vs. DownValues)
82742
Proving that ${x +y+n- 1 \choose n}= \sum_{k=0}^n{x+n-k-1 \choose n-k}{y+k-1 \choose k} $
143132
How to reverse the $n$ choose $k$ formula?