+129840 1/7+2/7^2+1/7^3+2/7^4+...
Note that we can split this into two different sums
[1/7 + 1/7^3 + 1/7^5+......] + [ 2/7^2 + 2/7^4 + 2/7^6+....]
The sum of the first series = [1/7] / [1 - 1/7^2 ] = 7/48
And the sum of the second series = [ 2/7^2] / [ 1 - 1/7^2] = 1/24
So.....the sum of the whole series = 7/48 + 1/24 = 7/48 + 2/48 = 9/48
