Sum of split terms 1 / (3 ^ 2-1) + 1 / (5 ^ 2-1) + 1 / (7 ^ 2-1) + .+ 1/[(2n+1)^2 -1] + … ..=

Sum of split terms 1 / (3 ^ 2-1) + 1 / (5 ^ 2-1) + 1 / (7 ^ 2-1) + .+ 1/[(2n+1)^2 -1] + … ..=

It's a test
Considering the characteristics of denominator, (2n + 1) ^ 2-1 = [(2n + 1) - 1] [(2n + 1) + 1] = 4N (n + 1)
And 1 / N (n + 1) = 1 / n-1 / (n + 1)
The final result is n / 4 (n + 1)