Can you explain where did the formula C(n)=2nCn/n+1 came from? Is there any video from CB on the topic?
Catalan number formula
It is beyond the scope of this course as it involves high level mathematics. If still interested, you can refer to this link. https://math.stackexchange.com/questions/337842/simplifying-catalan-number-recurrence-relation
Hope it Helps.