Find the sum of infinite terms of the series `3/1^2 + 5/(1^2 + 2^2) + 7/(1^2+2^2+3^2) + 9/(1^2+2^2+3^2+4^2)+...`

The sum to 50 terms of the series 3/1^2+5/(1^2+2^2)+7/(1^+2^2+3^2)+….+… is

Find the sum of n terms of the series 1.2^(2)+2.3^(2)+3.4^(2)+

Find the sum to n terms of the series 1.2.3+2.3.4+3.4.5+…

Let S_(n) be the sum to n terms of the series (2)/(1 ^(2)) + (5)/(1 ^(2) + 2^(2)) + (7)/(1^(2) + 2^(2) + 3^(2)) + (9)/(1 ^(2) + 2^(2) + 3 ^(2) + 6 ^(2))+ ……. then

Find the sum to n terms of the series: 1^(2)+(1^(2)+2^(2))+(1^(2)+2^(2)+3^(2))+