Question Number 31045 by abdo imad last updated on 02/Mar/18
$${simlify}\:{A}_{{n}} =\left({C}_{{n}} ^{\mathrm{1}} \right)^{\mathrm{2}} \:+\mathrm{2}\left({C}_{{n}} ^{\mathrm{2}} \right)^{\mathrm{2}} \:\:+{n}\:\left({C}_{{n}} ^{{n}} \right)^{\mathrm{2}} . \\ $$