" Find the sum of the first "n" terms of the series: "3+7+13+21+31+...

Find the sum of the 1^(st) n terms of the series 3+7+13+21+31+ …

Find the sum first 'n' terms of the series (3+7+13+21+31+..) ?

Find the sum of first n terms of the series 1.3 + 2.5 + 3.7 + 4.9 +…..

The sum of the first n terms of a series is 31, and the sum of the first n - 1 terms of the series is 20. What is the value of nth terms in the series?

Find the sum of n terms of the series : 5+7 +13 +31+85 + cdots .

The nth term of the series 3+7+13+21+... is

The nth term of the series 3+7+13+ 21+….... is

The n term of an A.P is 7n-5,find the sum of first 20 terms of the series.