Sum of the first 18 terms of the series 1 + 4 + 7 + .......

If the sum of the first n terms of the series

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

Find the sum of the first 8 terms of the series 2,6,18,54.

The sum of the first 10 terms of the series (5)/(1.2.3)+(7)/(2.3.9)+(9)/(3.4.27)+….. is

The sum of the first 10 terms of the series (5)/(1.2.3)+(7)/(2.3.9)+(9)/(3.4.27)+….. is

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?

Sum of the first n terms of the series 1/2+3/4+7/8+(15)/(16)+ is equal to