Question Number 117366 by Dwaipayan Shikari last updated on 11/Oct/20
$$\underset{{n}=\mathrm{1}} {\overset{\infty} {\sum}}\frac{\left(\mathrm{2}{n}\right)!}{{n}^{\mathrm{2}{n}} {n}!\left(\mathrm{2}{n}+\mathrm{1}\right)} \\ $$
n-1-2n-n-2n-n-2n-1-