Find the sum of the series – 1 + 5 + 11 +….to n terms.

Find the sum of the series : 11 + 103 + 1005 +.... to n terms.

Find the sum of the following series up to n terms: .6+. 66 +. 666+...

Find the sum of the series 1^2+3^2+5^2+ ton terms.

Find the sum of the following series up to n terms: 1^3/1+(1^3+2^3)/(1+3)+(1^3+2^3+3^3)/(1+3+5) +....

Find the sum of the following series to n terms 5+7+13+31+85+

Find the sum of n terms of the series whose nth terms is (i) n(n-1)(n+1) .

Find the sum of n terms of the series whose nth terms is (ii) n^(2)+3^(n) .

Find the sum of n terms of the series whose nth term is : 2^(n+1)+4(n+1)(n-2) .

Find the sum of n terms of the series whose nth term is : 2^(n-1)-1 .