Question Number 30551 by abdo imad last updated on 23/Feb/18
$$\:{find}\:\:{S}\:=\:\sum_{{n}\geqslant\mathrm{3}} \:\:\:\frac{\mathrm{1}}{\left({n}+\mathrm{1}\right)\left({n}−\mathrm{2}\right)\mathrm{2}^{{n}} }\:. \\ $$
find-S-n-3-1-n-1-n-2-2-n-