Find the sum `sumsum_(0leiltjlen)` `"^nC_i``"^nC_j`

Find the value of (sum sum)_(0<=i

Find the sum (i)sum_(0lei < jlen)sum . ^ nC_i .^ nC_j (ii)sum_(0lei le jlen)sum . ^ nC_i .^ nC_j (iii)sum_(i!=j).^ nC_i .^ nC_j

Find the sum sum_(k=1) (""^nC_(2k-1))/(2k)

Find the sum sum_(k=0)^n ("^nC_k)/(k+1)