Let S=123+143+163+⋯
And T=113+133+153+⋯.
Find S/T
S =sumfor(n, 1,∞ , (1/(2*n)^3))=0.1502570505........ T =sumfor(n, 1,∞ , (1/(2*n -1)^3))=1.051799728....... S/T =0.1502570505 / 1.051799728 =1 /7
Which is the same as:
∑[(1/(2*n)^3)), n, 1, ∞] / ∑[(1/(2*n - 1)^3)), n , 1, ∞] = 1/7