Timeline for An ambitiouser binomial coefficients sum
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
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| Nov 16, 2020 at 20:45 | vote | accept | Valentino | ||
| Nov 16, 2020 at 20:32 | answer | added | RobPratt | timeline score: 2 | |
| Nov 16, 2020 at 20:31 | comment | added | user64494 |
Sum[(-1)^i*Binomial[b, i]*Binomial[a + b - i - 1, a - i], {i, 0, k}] results in $$\frac{(-1)^{k+1} (k+1) (-a-b+k+1) \binom{b}{k+1} \binom{a+b-k-2}{a-k-1}}{a b} $$
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| Nov 16, 2020 at 20:29 | comment | added | RobPratt | wolframalpha.com/input/… | |
| Nov 16, 2020 at 20:24 | history | asked | Valentino | CC BY-SA 4.0 |