Sum to n terms :`1*3^2+3*5^2+5*7^2+...`

Find the sum of the following series to n term: 3xx1^2+5xx2^2+7xx3^2+............

Find the sum of the following series to n term: 3xx1^2+5xx2^2+7xx3^2+............

Find the sum of the following series to n term: 3.1^2+5.2^2+7.3^2+……..

Find the sum to 'n' terms of 3.1^(2)+5.2^(2)+7.3^(2)+ ........

Sum of n terms of series 1.3+3.5+5.7+....is

Sum to n terms the series (3)/(1 ^(2) . 2 ^(2)) + (5)/( 2 ^(2) . 3 ^(2)) + (7)/( 3 ^(2) . 4 ^(2)) +.............

Sum to infinite terms : 1/5-2/7^2+3/5^3-4/7^4+... .