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Timeline for New binomial coefficient identity?

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Jan 31, 2018 at 4:04 comment added Zurab Silagadze This identity also follows from the Saalschütz theorem (not immediately, but after some algebra) for the case $a=m+1/2$, $b=m+n+1$, $c=m+3/2$, because the sum now is $$\frac{\binom{n+m}{n-m}}{2m+1} {_3F_2}(m+1/2,m+n+1,-(n-m);m+3/2,2m+1;1).$$
Jan 31, 2018 at 3:17 comment added Zurab Silagadze Thanks! I obtained the identity from the Clausen’s identity for the Legendre polynomials. A generalization to the associated Legendre functions produces $$\sum\limits_{k=m}^n\frac{(-1)^{k-m}}{2k+1}\binom{n+k}{n-k}\binom{2k}{k-m}=\frac{1}{2n+1}.$$
Jan 31, 2018 at 3:07 vote accept Zurab Silagadze
Jan 30, 2018 at 14:41 history edited Ira Gessel CC BY-SA 3.0
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Jan 30, 2018 at 14:18 history edited Martin Sleziak CC BY-SA 3.0
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Jan 30, 2018 at 14:13 history answered Ira Gessel CC BY-SA 3.0