Timeline for combinatoric proof $\sum_{i=0}^{n}(-1)^i\binom{n}{i}\binom{n-i+k-1}{k}=\binom{k-1}{k-n}$
Current License: CC BY-SA 4.0
1 event
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 9, 2021 at 20:03 | history | answered | Fedor Petrov | CC BY-SA 4.0 |