what your doing here is calculating the formula for integer values from n=1 to infinity and adding them all up. In both the series you have reached n=4 and you want sums for n=5,6, and 7, so just plug these numbers into the 1/5n - 1 and 1/n^2 to find the next 3 terms in the series i.e for n=5

1/5n - 1 = 1/(5*5)-1 = 1/24.....6 and 7 are 1/29 and 1/34

You need to calculate for all values of n again for the 1/n^2 formula as the series you currently have is incorrect

Hope this helps